Updated openstack/openstack
Project: openstack/nova  b52a63e3b694b90f883f64d2d9c464237d07a2d4

VMware: prevent image snapshot if no root disk defined

If there is no root disk defined then the snapshot should
throw an exception.

Change-Id: I0549b8ca9ba41b734277600cb66a74b27ca72d88
Related-bug: #1297605