Updated openstack/openstack
Project: openstack/nova  c764b78b0aab53f09f5d46c24e1d914995a9f86b

VMware: validate that VM exists on backend prior to deletion

Attempting to delete an instance that does not exist on the backend
throws an exception (for example UnregisterVM may return this when
running the CI).

Change-Id: I1b95caec2dad6580db576aa6f80f47913b7c066e
Closes-bug: #1300788