Code review comment for lp:~rconradharris/nova/lp794672

Mainly this came out of my discussion with Rick about getting around the bottlenecks of hitting the single glance server when doing 500 builds at once. The Glance server was getting slammed hard from the sheer number of simultaneous builds.

I agree that full production environment would utilize load balancers to properly set load up across multiple glance-api. For a user with a smaller environment, or for stress testing, the patch might be useful to some.