[Libguestfs] [PATCH v2 0/2] v2v: Add -o openstack target.

v1 was here: https://www.redhat.com/archives/libguestfs/2018-August/thread.html#00287 v2: - The -oa option now gives an error; apparently Cinder cannot generally control sparse/preallocated behaviour, although certain Cinder backends can. - The -os option maps to Cinder volume type; suggested by Matt Booth. - Add a simple test.