Merge "Add 'rhel' for RPM distros"

docker/ceilometer/ceilometer-alarm/Dockerfile.j2

docker/ceilometer/ceilometer-api/Dockerfile.j2

docker/ceilometer/ceilometer-central/Dockerfile.j2

docker/ceilometer/ceilometer-collector/Dockerfile.j2

docker/ceilometer/ceilometer-compute/Dockerfile.j2

docker/ceilometer/ceilometer-notification/Dockerfile.j2

docker/ceph/ceph-base/Dockerfile.j2

docker/cinder/cinder-api/Dockerfile.j2

docker/cinder/cinder-base/Dockerfile.j2

docker/cinder/cinder-volume/Dockerfile.j2

docker/designate/designate-api/Dockerfile.j2

docker/designate/designate-backend-bind9/Dockerfile.j2

docker/designate/designate-base/Dockerfile.j2

docker/designate/designate-central/Dockerfile.j2

docker/designate/designate-mdns/Dockerfile.j2

docker/designate/designate-poolmanager/Dockerfile.j2

docker/designate/designate-sink/Dockerfile.j2

docker/glance/glance-base/Dockerfile.j2

docker/gnocchi/gnocchi-api/Dockerfile.j2

docker/gnocchi/gnocchi-statsd/Dockerfile.j2