Provide a floating VIP for the cluster

For outside access to the OpenStack services in a cluster, we need to provide one (or more) floating vips that can be used to access OpenStack services. This may happen through future kubernetes features (https://github.com/GoogleCloudPlatform/kubernetes/issues/1161) or it may be possible to realize this with something like Keepalived or a hardware load balancer. If a kubernetes deployed openstack environment is going to be useful we need a plan for access from outside the kubernetes cluster.