Comment 21 for bug 1371677

Since https://review.openstack.org/#/c/123774/ merged there is a significant drop off in the race, so looks like that stemmed the bleeding. This is probably not a critical rc1 issue now. We should still put something in the libvirt driver to check if the volume bdm exists before calling the blocking blockdev command to get the volume size, but that could be a follow on improvement.