Use addClassResourceCleanup in test_container_sync

This patch is to use addClassResourceCleanup for the
test_container_sync.

Change-Id: Ic534495de3d369dd9b69adc13dcc6bfb7edc9e4c
diff --git a/tempest/api/object_storage/test_container_sync.py b/tempest/api/object_storage/test_container_sync.py
index 042d288..0477d91 100644
--- a/tempest/api/object_storage/test_container_sync.py
+++ b/tempest/api/object_storage/test_container_sync.py
@@ -72,14 +72,12 @@
             (cls.container_client_alt, cls.object_client_alt)
         for cont_name, client in cls.clients.items():
             client[0].create_container(cont_name)
+            cls.addClassResourceCleanup(base.delete_containers,
+                                        cont_name,
+                                        client[0],
+                                        client[1])
             cls.containers.append(cont_name)
 
-    @classmethod
-    def resource_cleanup(cls):
-        for client in cls.clients.values():
-            cls.delete_containers(client[0], client[1])
-        super(ContainerSyncTest, cls).resource_cleanup()
-
     def _test_container_synchronization(self, make_headers):
         # container to container synchronization
         # to allow/accept sync requests to/from other accounts