Updated openstack/openstack
Project: openstack-dev/devstack  813ba48a3ce830306cf847b44883f32b72befb14
null
Add xenserver image

By adding a separate entry for xenserver, it will enforce the gate to
cache cirros-0.3.0-x86_64-disk.vhd.tgz.

Change-Id: Ibfd4618e98f079a53fc286f5e95f18a3d658e4d2