Using the pattern established in [1], install glance services in a way
that allows for minimal interruptions during upgrades. Upgrades are
serialized such that only one glance host is unavailable at a time.
[1] Change I0bdb51ce0d8b3b9a145d29ef6808e1fe595924e2
Depends-On: I4a4d8f23f05a16d25878340ede019be7ccdb7196
Depends-On: I743089b9a4f13ce974cbeb9cc91b67b013f2f323
Change-Id: I1c70563c7b5bb3e5666821e9288d723b26d9903e