Fix daemon panic use wrong graphdriver with --live-restore flag

Signed-off-by: Lei Jitang <leijitang@huawei.com>

daemon/daemon.go

@@ -651,7 +651,7 @@ func (daemon *Daemon) Shutdown() error {
 	daemon.shutdown = true
 	// Keep mounts and networking running on daemon shutdown if
 	// we are to keep containers running and restore them.
-	if daemon.configStore.LiveRestore {
+	if daemon.configStore.LiveRestore && daemon.containers != nil {
 		// check if there are any running containers, if none we should do some cleanup
 		if ls, err := daemon.Containers(&types.ContainerListOptions{}); len(ls) != 0 || err != nil {
 			return nil