Disable and stop docker when the CRI is containerd

Previously the docker service was disabled but kept running.
And if stopped, would be restarted by the docker socket.

Docker can be fully disabled and stopped when using containerd.

Change-Id: Ic3529106806f90dcafc24006c6c0dbc30e33766b

Author: tghartland

magnum/drivers/common/templates/kubernetes/fragments/install-cri.sh

@@ -8,7 +8,8 @@ set -x
 ssh_cmd="ssh -F /srv/magnum/.ssh/config root@localhost"
 
 if [ "${CONTAINER_RUNTIME}" = "containerd"  ] ; then
-    $ssh_cmd systemctl disable docker
+    $ssh_cmd systemctl disable docker.service docker.socket
+    $ssh_cmd systemctl stop docker.service docker.socket
     if [ -z "${CONTAINERD_TARBALL_URL}"  ] ; then
         CONTAINERD_TARBALL_URL="https://github.com/containerd/containerd/releases/download/v${CONTAINERD_VERSION}/cri-containerd-cni-${CONTAINERD_VERSION}-linux-amd64.tar.gz"
     fi