Refix transient test failures

Commit a10bd7a fixed the issue with
transient test failures, but during the rebase of the commit
be754ff the fix was lost.

Fixes bug 1077065

Change-Id: I14311f56e6dd0103620b58e64bf0c78c7e32f61c

tests/test_service.py

@@ -60,13 +60,16 @@ def assertEqualTokens(self, a, b):
         """
         def normalize(token):
             token['access']['token']['id'] = 'dummy'
-            # truncate to eliminate timing problems
-            issued = token['access']['token']['issued_at']
-            token['access']['token']['issued_at'] = issued[:-8]
-            # truncate to eliminate timing problems
-            expires = token['access']['token']['expires']
-            token['access']['token']['expires'] = expires[:-3]
+            del token['access']['token']['expires']
+            del token['access']['token']['issued_at']
             return token
+
+        self.assertCloseEnoughForGovernmentWork(
+            timeutils.parse_isotime(a['access']['token']['expires']),
+            timeutils.parse_isotime(b['access']['token']['expires']))
+        self.assertCloseEnoughForGovernmentWork(
+            timeutils.parse_isotime(a['access']['token']['issued_at']),
+            timeutils.parse_isotime(b['access']['token']['issued_at']))
         return self.assertDictEqual(normalize(a), normalize(b))