Add logging handler for openstack_auth in the tests

Without it, log output below ERROR level can also be displayed in the
tests output.

Change-Id: I342b20fc26468a41843496f11db3e0079b50505c
Closes-Bug: #1218462

openstack_dashboard/test/settings.py

@@ -151,6 +151,10 @@ LOGGING['loggers'].update(
             'handlers': ['test'],
             'propagate': False,
         },
+        'openstack_auth': {
+            'handlers': ['test'],
+            'propagate': False,
+        },
         'novaclient': {
             'handlers': ['test'],
             'propagate': False,