Comment 15 for bug 1813147

This is probably the next one to squash:

2019-02-04 16:58:37.674764 | ubuntu-bionic | Captured stderr:
2019-02-04 16:58:37.674800 | ubuntu-bionic | ~~~~~~~~~~~~~~~~
2019-02-04 16:58:37.675041 | ubuntu-bionic | b'/home/zuul/src/git.openstack.org/openstack/nova/.tox/py36/lib/python3.6/site-packages/oslo_service/threadgroup.py:193: DeprecationWarning: Calling add_timer() with arguments to the callback function is deprecated. Use add_timer_args() instead.'
2019-02-04 16:58:37.675100 | ubuntu-bionic | b' DeprecationWarning)'
2019-02-04 16:58:37.675135 | ubuntu-bionic | b''

39 occurrences in a py35 unit test job today.