Description of problem:
On the node which runs the nova-api service the following error shows up when running nova-manage db online_data_migrations:

[root@overcloud-serviceapi-0 heat-admin]# nova-manage db online_data_migrations
Traceback (most recent call last):
  File "/bin/nova-manage", line 10, in <module>
    sys.exit(main())
  File "/usr/lib/python2.7/site-packages/nova/cmd/manage.py", line 1430, in main
    config.parse_args(sys.argv)
  File "/usr/lib/python2.7/site-packages/nova/config.py", line 50, in parse_args
    rpc.init(CONF)
  File "/usr/lib/python2.7/site-packages/nova/rpc.py", line 74, in init
    TRANSPORT = create_transport(get_transport_url())
  File "/usr/lib/python2.7/site-packages/nova/rpc.py", line 154, in get_transport_url
    return messaging.TransportURL.parse(CONF, url_str, TRANSPORT_ALIASES)
  File "/usr/lib/python2.7/site-packages/oslo_messaging/transport.py", line 398, in parse
    url = url or conf.transport_url
  File "/usr/lib/python2.7/site-packages/oslo_config/cfg.py", line 2271, in __getattr__
    raise NoSuchOptError(name)
oslo_config.cfg.NoSuchOptError: no such option transport_url in group [DEFAULT]


Version-Release number of selected component (if applicable):
latest osp11 puddle tht with https://review.openstack.org/#/c/405241/ applied

How reproducible:
2/2

Steps to Reproduce:
1. Run the upgrade prcedure

Actual results:
Upgrade fails while upgrading the role which contains the nova api service

Expected results:
Upgrade should pass

Additional info: