Add missing glance multi-store configurations

While removing registry [1] we by mistake removed some code related to
multiple store configuration for glance. This must be happened during
resolving merged conflicts.

Adding it back.

[1] https://review.opendev.org/708062

Change-Id: I2b84f7b7c51b7b20765a06b48c75006fd2e8ab71
1 file changed