This allows Kubernetes to reschedule the container in case a required
variable is missing, for example when the Kubernetes pod is started
before the service.
Additionally, define the KEYSTONE_ADMIN_SERVICE_HOST and
KEYSTONE_PUBLIC_SERVICE_HOST variables to their common version if not
already set to allow usage outside of Kubernetes with docker link
feature.
Change-Id: Ie0966c18076a770e4031bbf5f777dd1be0ba20bc
Closes-Bug: 1398632
21f28309e7