tempest: re-enable shelve tests for train

The dependent nova fix resolves the issue with rbd and
shelve/unshelve testing in tempest. Re-enabling the test
needs to be branch-specific since devstack-plugin-ceph
is branch-less but the fixes in nova will be branch
specific so we don't want to enable this on any nova
branch that does not have the fix since it would break
the job on those branches.

Related-Bug: #1653953

Depends-On: https://review.opendev.org/457886/

Co-Authored-By: Matt Riedemann <mriedem.os@gmail.com>

Change-Id: Ifbfc15033020c430a93574f2726b2279c9be130d

devstack/plugin.sh

@@ -97,12 +97,13 @@ elif [[ "$1" == "stack" && "$2" == "test-config" ]]; then
     if is_service_enabled tempest; then
         iniset $TEMPEST_CONFIG compute-feature-enabled swap_volume False
 
-        # This is only being set because the tempest test
-        # test_shelve_unshelve_server fails with an
-        # "After unshelve, shelved image is not deleted"
-        # failure.  Re-enable this feature when that test is fixed.
-        # https://review.openstack.org/#/c/471352/
+        # Only enable shelve testing for branches which have the fix for
+        # nova bug 1653953.
+        if [[ "$TARGET_BRANCH" =~ stable/(ocata|pike|queens|rocky|stein) ]]; then
             iniset $TEMPEST_CONFIG compute-feature-enabled shelve False
+        else
+            iniset $TEMPEST_CONFIG compute-feature-enabled shelve True
+        fi
     fi
 fi