Fix update snapshot-quotas on delete.

The merge from stable to RC of the snapshot quota
fixes missed the new CONF usage and as a result the
setting was always ignored on delete and therefore
quotas were not decremented on delete.

This patch changes CONF back to FLAGS for that call and
resolves the issue.

Fixes bug: 1173365

Change-Id: I7af69d5078ebcc5547e08d543a2dcfd0ca3f6c4b

cinder/volume/manager.py

@@ -505,7 +505,7 @@ def delete_snapshot(self, context, snapshot_id):
 
         # Get reservations
         try:
-            if CONF.no_snapshot_gb_quota:
+            if FLAGS.no_snapshot_gb_quota:
                 reservations = QUOTAS.reserve(context,
                                               project_id=project_id,
                                               snapshots=-1)