per-feature extension method in api/neutron.py should be removed

[Akihiro Motoki]

In api/neutron.py, is_xxxxx_exntension_supproted() is defined per feature, but this style doesn't scale.
is_extension_supported() is memoized and if there is no special reason is_extension_supported() should be used directly.

is_quotas_extension_supported() is an exception because it has extra logic.

We already have rough consensus on the direction.
http://eavesdrop.openstack.org/meetings/horizon/2014/horizon.2014-07-22-16.00.log.html#l-140

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/109345

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/109345
Committed: https://git.openstack.org/cgit/openstack/horizon/commit/?id=cc25bd602626af194650e3ce3888992c9d9a4ff2
Submitter: Jenkins
Branch: master

commit cc25bd602626af194650e3ce3888992c9d9a4ff2
Author: Akihiro Motoki <email address hidden>
Date: Thu Jul 24 17:56:18 2014 +0900

    Remove per-feature extension check method in api/neutron

    Change-Id: Ie1309d5a51e86a37c640e169d66c73724fc1c9ff
    Closes-Bug: #1348075