This review is modified to include a patch to resolve bug #1793137
which is due to a bug in nova-lxd where the wrong pool name (lxd) is
used with zfs if lxd is new enough that the storage.zfs_pool_name key
is missing from the config. This is the case on bionic and snap
installed lxd.
Closes-Bug: #1713807
Related-Bug: #1793137
Change-Id: I1123d9882bdb00e9183424b363fc3d1ff25f2346