Trove-taskmanager report "AttributeError" in log while running periodic task "publish_quota_notifications"

trove-taskmanager periodically report error logs while running periodic task "publish_quota_notifications" in trove Mitaka.

In trove/taskmanager/manager.py there is a periodic taks named "publish_quota_notifications", .In this function,trove called novaclient to list all tenants, but there is no tenant list API in Mitaka novaclient, so trove-taskmanager throw an error.

To reproduce the problem, keep taskmanager working. and after a while error info will show.

The error logs in trove-taskmanager.log:

2017-07-21 06:09:44.291 44042 DEBUG oslo_service.periodic_task [-] Running periodic task Manager.publish_quota_notifications run_periodic_tasks /usr/lib/python2.7/site-packages/oslo_service/periodic_task.py:215
2017-07-21 06:09:44.295 44042 ERROR oslo_service.periodic_task [-] Error during Manager.publish_quota_notifications
2017-07-21 06:09:44.295 44042 ERROR oslo_service.periodic_task Traceback (most recent call last):
2017-07-21 06:09:44.295 44042 ERROR oslo_service.periodic_task File "/usr/lib/python2.7/site-packages/oslo_service/periodic_task.py", line 220, in run_periodic_tasks
2017-07-21 06:09:44.295 44042 ERROR oslo_service.periodic_task task(self, context)
2017-07-21 06:09:44.295 44042 ERROR oslo_service.periodic_task File "/usr/lib/python2.7/site-packages/trove/taskmanager/manager.py", line 513, in publish_quota_notifications
2017-07-21 06:09:44.295 44042 ERROR oslo_service.periodic_task for tenant in nova_client.tenants.list():
2017-07-21 06:09:44.295 44042 ERROR oslo_service.periodic_task AttributeError: 'Client' object has no attribute 'tenants'