Add a scenario test for classless PTR delegation

This patch adds a scenario test for classless in-addr.arpa delegation
(RFC 2317).

Change-Id: I11157615a1273d4f087e725cc09de3ad64e07d29
diff --git a/designate_tempest_plugin/tests/rbac_utils.py b/designate_tempest_plugin/tests/rbac_utils.py
index fa66410..aa8bb6a 100644
--- a/designate_tempest_plugin/tests/rbac_utils.py
+++ b/designate_tempest_plugin/tests/rbac_utils.py
@@ -302,7 +302,7 @@
 
             self.assertEqual(expected_count, len(result_objs),
                              message='Credential {} saw {} objects when {} '
-                             'was expected.'.format(cred, len(result),
+                             'was expected.'.format(cred, len(result_objs),
                                                     expected_count))
 
     def check_list_IDs_RBAC_enforcement(