Don't use glance when verifying images.
Don't use glance when verifying images.

Using glance means that admin contexts need to know how to use
keystone when that is enabled. Its safer to avoid calling glance
at all from inside the periodic task.

This should resolve bug 934464.

Change-Id: Ib730e3f57721fca7080d90ae80b5f8916c1dc76c

n0ano/gantt,n0ano/gantt