Comment 1 for bug 1628280

e.g. from http://logs.openstack.org/46/377746/1/check/gate-designate-python34-db/6263198/testr_results.html.gz:
    Traceback (most recent call last):
      File "/home/jenkins/workspace/gate-designate-python34-db/.tox/py34/lib/python3.4/site-packages/mock/mock.py", line 1305, in patched
        return func(*args, **keywargs)
      File "/home/jenkins/workspace/gate-designate-python34-db/designate/tests/test_agent/test_backends/test_denominator.py", line 82, in test_update_zone
        self.backend.update_zone(zone)
      File "/home/jenkins/workspace/gate-designate-python34-db/designate/backend/agent_backend/impl_denominator.py", line 185, in update_zone
        output = self.denominator.get_records(zone_name)
      File "/home/jenkins/workspace/gate-designate-python34-db/designate/backend/agent_backend/impl_denominator.py", line 54, in get_records
        return self._execute(['record', '-z', zone, 'list'], kwargs)
      File "/home/jenkins/workspace/gate-designate-python34-db/designate/backend/agent_backend/impl_denominator.py", line 81, in _execute
        LOG.debug(('Executing Denominator call: %s' % ' '.join(call)))
    TypeError: sequence item 8: expected str instance, bytes found