The glance-cache.conf is used by the glance-cache-prefetcher command
which requires access to backend store. Thus all store options should
be added to the glance-cache.conf file so that backend store can be
loaded properly.
Closes-Bug: #2034893
Change-Id: I8f0b2be8b138d267364f20ff81876902b225d29e
10d7bbdeef