clean up API versions

[Ivan Kolodyazhny]

cinderclient has a lot of duplicated code to work with different API versions. We have to refactor to get rid of copy-paste and make adding new features easier

Related issue in Cinder API: https://bugs.launchpad.net/cinder/+bug/1627921/

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/400963

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/400963
Committed: https://git.openstack.org/cgit/openstack/python-cinderclient/commit/?id=603c615ae59a8b6c24811b39ad05f26228ef5868
Submitter: Jenkins
Branch: master

commit 603c615ae59a8b6c24811b39ad05f26228ef5868
Author: Ivan Kolodyazhny <email address hidden>
Date: Tue Nov 22 22:51:47 2016 +0200

    Refactor v2 and v3 APIs support

    Now v2 API uses code from v3. It's confusing and logically incorrect.
    This patch makes v3 API as an extended version of v2.

    The next patches related to this bug duplicated code between v1 and v2,
    v2 and v3 will be removed.

    Change-Id: I90a2b713556e91db69270a03ef6b798e08f93f90
    Partial-Bug: #1643584

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/414605

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/414605
Committed: https://git.openstack.org/cgit/openstack/python-cinderclient/commit/?id=204b15ab13004e3d5ac1ec4d0dbd3fe94bb2a8fd
Submitter: Jenkins
Branch: master

commit 204b15ab13004e3d5ac1ec4d0dbd3fe94bb2a8fd
Author: Ivan Kolodyazhny <email address hidden>
Date: Fri Dec 23 16:36:19 2016 +0200

    Removed unnecessary 'service_type' decorator

    @utils.service_type was introduced with 'Initial split from
    python-novaclient' commit and used for CLI. Now both Python and
    Command-line APIs for each version work well without this decorator.

    Unused 'get_service_type' function is removed too.

    'utils.retype_method' removed as well because everything works well
    without it.

    Change-Id: Ic2470d8ca9d581b7c47da8d7e6a414c3c78ad27a
    Partial-Bug: #1643584
    Related-Bug: #1621126

[Sean McGinnis (sean-mcginnis)]

Unassigning due to no activity for > 6 months.