core: adding ovirt glance repository

We recently added a public Glance repository in glance.ovirt.org
This patch adds it as a provider + storage domain, to be used by
default in oVirt installations.

Change-Id: I66215abe4c68e2a7ffe919124745be6136f8f550
Signed-off-by: Oved Ourfali <oourfali@redhat.com>