Remove use of deprecated config options for volume API selection

Tempest has moved the Volume APIs testing to v3 as default and can be run
under v2 API via catalog_type.
- https://review.opendev.org/#/q/topic:volume-default-testing-v3+(status:open+OR+status:merged)

Below config options were deprecated since Rocky and now Tempest is going
to remove those (Needed-By patch):
    * ``CONF.volume-feature-enabled.api_v2``
    * ``CONF.volume-feature-enabled.api_v3``

Change-Id: I600ac88dbed8697cd1efe009fd46195f934f3eb6
Needed-By: https://review.opendev.org/#/c/698754/
2 files changed