[stable-only]: Set system_scope_supported

There is a new config option 'system_scope_supported'
added in glance-tempest-plugin
- https://review.opendev.org/c/openstack/glance-tempest-plugin/+/882363

which control whether or not to test the system scope asserts.

System scope is supported in glance only till stable/yoga so
setting the new flag to True for <=stable/yoga

Depends-On: https://review.opendev.org/c/openstack/glance-tempest-plugin/+/882363

Change-Id: I0e4a65a9887505e63b824a40c0dacea4a8396ea0
(cherry picked from commit fece4f466c)

lib/tempest

@@ -675,6 +675,8 @@ function configure_tempest {
     done
 
     iniset $TEMPEST_CONFIG enforce_scope glance "$GLANCE_ENFORCE_SCOPE"
+    # NOTE(gmann): system scope is supported for <=stable/yoga only
+    iniset $TEMPEST_CONFIG glance_api system_scope_supported "True"
 
     iniset $TEMPEST_CONFIG enforce_scope cinder "$CINDER_ENFORCE_SCOPE"