diff --git a/tempest/api/compute/servers/test_list_servers_negative.py b/tempest/api/compute/servers/test_list_servers_negative.py
index 0f35ee5..db9bdc1 100644
--- a/tempest/api/compute/servers/test_list_servers_negative.py
+++ b/tempest/api/compute/servers/test_list_servers_negative.py
@@ -15,6 +15,7 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+import datetime
 
 from tempest.api import compute
 from tempest.api.compute import base
@@ -170,7 +171,8 @@
     @attr(type='gate')
     def test_list_servers_by_changes_since(self):
         # Servers are listed by specifying changes-since date
-        changes_since = {'changes-since': '2011-01-01T12:34:00Z'}
+        since = datetime.datetime.utcnow() - datetime.timedelta(minutes=2)
+        changes_since = {'changes-since': since.isoformat()}
         resp, body = self.client.list_servers(changes_since)
         self.assertEqual('200', resp['status'])
         # changes-since returns all instances, including deleted.
diff --git a/tempest/services/identity/v3/json/endpoints_client.py b/tempest/services/identity/v3/json/endpoints_client.py
old mode 100755
new mode 100644
diff --git a/tempest/services/identity/v3/xml/endpoints_client.py b/tempest/services/identity/v3/xml/endpoints_client.py
old mode 100755
new mode 100644