This was still using glanceclient-style calls despite us having switched
all image command to SDK way back in 5.2.0 (Ussuri). It therefore hasn't
worked since then, so we remove without deprecation.
Change-Id: Ibea79ea10bb272cba194debfe4bcbaeebf3875b7
Signed-off-by: Stephen Finucane <stephenfin@redhat.com>