This is marked upstream as blocked on a cinder change.
The cinder change is https://review.openstack.org/#/c/30974/ , initially submitted in may, with a new patch set updated yesterday. So there is still activity on this bp, though we're coming up to the deadline for nova.
This cinder change was merged and the nova patch is under review.
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.
For information on the advisory, and where to find the updated
files, follow the link below.
If the solution does not work for you, open a new bug report.