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/
diff --git a/barbican_tempest_plugin/tests/scenario/manager.py b/barbican_tempest_plugin/tests/scenario/manager.py
index 8be324a..f91e27b 100644
--- a/barbican_tempest_plugin/tests/scenario/manager.py
+++ b/barbican_tempest_plugin/tests/scenario/manager.py
@@ -75,10 +75,8 @@
         cls.security_group_rules_client = (
             cls.os_primary.security_group_rules_client)
 
-        if (CONF.volume_feature_enabled.api_v2 or
-           CONF.volume_feature_enabled.api_v3):
-            cls.volumes_client = cls.os_primary.volumes_client_latest
-            cls.snapshots_client = cls.os_primary.snapshots_client_latest
+        cls.volumes_client = cls.os_primary.volumes_client_latest
+        cls.snapshots_client = cls.os_primary.snapshots_client_latest
 
     # ## Test functions library
     #