update callback subscriptions of object methods to use decorator

[Kevin Benton]

We can now use @registry.receives("resource", ["event1", "event2"]) to decorate methods in a class that should be subscribed to the callback manager when its instances are created.

This improves readability for two purposes:

1. Using the decorator right above the method makes it easy to see when looking at the code when the method is going to be called instead of having to search for the component that subscribes it.
2. We can stop overriding __new__ in class definitions just for registry subscriptions, which makes the class definitions a little cleaner.

See https://review.openstack.org/#/c/438489/ and https://review.openstack.org/#/c/436353/ for examples.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/438718

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/438721

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/438724

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/439062

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/439076

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/438721
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=f448fd2229a5e6cdc92dd215b8e499e85984511f
Submitter: Jenkins
Branch: master

commit f448fd2229a5e6cdc92dd215b8e499e85984511f
Author: Cedric Brandily <email address hidden>
Date: Mon Feb 27 23:19:41 2017 +0100

    Use registry.receives decorator in neutron.db.l3_hamode_db

    Switch to registry.receives decorator in neutron.db.l3_hamode_db

    Partial-Bug: #1668262
    Change-Id: I57b9f268b2d26f9605452d57622d2c222625e2d2

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/439738

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/439741

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/439745

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/439750

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/439918

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/438724
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=e1edf6f276736db9f2f8607d63ce68a761678ddd
Submitter: Jenkins
Branch: master

commit e1edf6f276736db9f2f8607d63ce68a761678ddd
Author: Cedric Brandily <email address hidden>
Date: Mon Feb 27 23:26:57 2017 +0100

    Use registry.receives decorator in neutron.db.availability_zone.router

    Switch to registry.receives decorator in neutron.db.availability_zone.router

    Partial-Bug: #1668262
    Change-Id: Ib4e34159bf71a749eddf945fb942f679da7bacd0

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/439745
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=4f237819cf20e83e738fbe5f66f9d87d8932cfd0
Submitter: Jenkins
Branch: master

commit 4f237819cf20e83e738fbe5f66f9d87d8932cfd0
Author: Cedric Brandily <email address hidden>
Date: Tue Feb 28 18:45:56 2017 +0100

    Use @registry.receives in neutron.services.qos.drivers.base

    Switch to registry.receives decorator in neutron.services.qos.drivers.base

    Change-Id: If7532e0f08824523b55f0de53a59525d519ca7f9
    Partial-Bug: #1668262

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/439741
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=2f4a5f8f37286b09d74ed18f562d09b37095a448
Submitter: Jenkins
Branch: master

commit 2f4a5f8f37286b09d74ed18f562d09b37095a448
Author: Cedric Brandily <email address hidden>
Date: Wed Mar 1 18:43:06 2017 +0100

    Use registry.receives decorator in driver_controller

    Switch to registry.receives decorator in
    neutron.services.l3_router.service_providers.driver_controller.

    Change-Id: I96b32365ef15c5e7c1f54cf58f1451e978f6bd91
    Partial-Bug: #1668262

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/438718
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=374de0ad49986b2f80a0bf3e16d16c48c3f8f7c0
Submitter: Jenkins
Branch: master

commit 374de0ad49986b2f80a0bf3e16d16c48c3f8f7c0
Author: Cedric Brandily <email address hidden>
Date: Mon Feb 27 23:08:24 2017 +0100

    Use registry.receives decorator in neutron.db.l3_dvr_db

    Switch to registry.receives decorator in neutron.db.l3_dvr_db

    Partial-Bug: #1668262
    Change-Id: I01b0711e5a4f4729ce76519522271577516cacec

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/439076
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=e3cd8e9bdf7f5571517e87bb9d681e9a234c682c
Submitter: Jenkins
Branch: master

commit e3cd8e9bdf7f5571517e87bb9d681e9a234c682c
Author: Cedric Brandily <email address hidden>
Date: Tue Feb 28 18:45:56 2017 +0100

    Use registry.receives decorator in neutron.db.dvr_mac_db

    Switch to registry.receives decorator in neutron.db.dvr_mac_db.

    Change-Id: I7f1426adabe1d97b8df11d561454972354c23b14
    Partial-Bug: #1668262

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/442354

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/439918
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=20097d44bf686c74c3dea236b730af51162f9408
Submitter: Jenkins
Branch: master

commit 20097d44bf686c74c3dea236b730af51162f9408
Author: Cedric Brandily <email address hidden>
Date: Tue Feb 28 18:45:56 2017 +0100

    Use @registry.receives in neutron.services.trunk

    Switch to registry.receives decorator in neutron.services.trunk package.

    Partial-Bug: #1668262
    Change-Id: Iad3d99d958eb906b1cf2370378149ba1a4b209f4

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/439738
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=a5e04fbd84b96e306db3d3ed6140fa82e7441495
Submitter: Jenkins
Branch: master

commit a5e04fbd84b96e306db3d3ed6140fa82e7441495
Author: Cedric Brandily <email address hidden>
Date: Wed Mar 1 18:33:57 2017 +0100

    Use registry.receives decorator in neutron.notifiers.nova

    Switch to registry.receives decorator in neutron.notifiers.nova.

    Partial-Bug: #1668262
    Change-Id: I50f61f97ded73cd3b7f18ac97d8d4b918554e098

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/439750
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=e4495bfe0a4fe97c206d279cd7fb49460e1254b8
Submitter: Jenkins
Branch: master

commit e4495bfe0a4fe97c206d279cd7fb49460e1254b8
Author: Cedric Brandily <email address hidden>
Date: Tue Feb 28 18:45:56 2017 +0100

    Use @registry.receives in neutron.services.segments.plugin

    Switch to registry.receives decorator in neutron.services.segments.plugin.

    Change-Id: Ic9b5a2ce2b1dac2ed912a72c9698d19c2cf4ce9d
    Partial-Bug: #1668262

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/439062
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=cd39505f89ccbd8ca22cfbd3f8fd6ccaffab186f
Submitter: Jenkins
Branch: master

commit cd39505f89ccbd8ca22cfbd3f8fd6ccaffab186f
Author: Cedric Brandily <email address hidden>
Date: Tue Feb 28 18:05:16 2017 +0100

    Use registry.receives decorator in neutron.db.db_base_plugin_v2

    Switch to registry.receives decorator in neutron.db.db_base_plugin_v2

    Partial-Bug: #1668262
    Change-Id: I205bac32d94bc40b737f7b2e90f559925821110a

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/442354
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=67f39774546d3edddbccfa226a823a8a292f5a2d
Submitter: Jenkins
Branch: master

commit 67f39774546d3edddbccfa226a823a8a292f5a2d
Author: Cedric Brandily <email address hidden>
Date: Tue Feb 28 18:45:56 2017 +0100

    Use registry.receives decorator in neutron.db.l3_db

    Switch to registry.receives decorator in neutron.db.l3_db.

    Partial-Bug: #1668262
    Change-Id: Ia8ac4f510c003667cac95f76dea0e9ae55159878