The openstack auth plugin was deprecated in v1.11 in favor of the
"client-keystone-auth" credential plugin. This change removes the
plugin in v1.19 (eight releases seems more than sufficient notice).
Signed-off-by: Monis Khan <mok@vmware.com>
Kubernetes-commit: 0beb8ea0fef3556474b3a713a2203d4edbbb4fc2
