fix glance_store testing

glance_store is currently install from pypi in devstack, however it
doesn't have the new test job definitions, which means that none of
it's integration tests are running.

Which explains why the broken devstack support for glance_store wasn't
caught.

We need to fix this soon.

If4794bc710a2946c70f550bc7823a9dc0f539aa1 creates a tool in devstack
that helps us find issues like this.

Change-Id: I73cab34f99428b850e836a76df106ab4d236ee3e
Merge "fix glance_store testing"