Updated openstack/openstack
Project: openstack/nova  2b647bea0a822744a70ca6600138b5f762591836

fix import of oslo.concurrency

It's now oslo_concurrency, and importing the old symbol triggers a
deprecation warning. There were 2 instances of this unfixed.

Change-Id: Ib63da2d845843410634a1df0261af33b973daf32