Comment 9 for bug 1649341

The transport_url is required to be passed in because of limitations in oslo.messaging, as seen in the code comment here:

https://github.com/openstack/nova/blob/d9d9071af250409c0102e7a25e35d7521812172d/nova/cmd/manage.py#L1211

melwitt would be the person to ask about that, since I think she was working an oslo blueprint for this in newton.