It's possible for glance-api to get stuck in a loop starting when
the backend is swift, and python-swiftclient is not present on
the system.
Depends-On: I65fb0736e9fa9e68c3c7877cf6caf228c49eb82d
Change-Id: I1eeb9f12cf82961ae820067ad8fe91d096d1d6e1
Closes-bug: #1632143
(cherry picked from commit 33f96d71ed)