control: Implement service command 'stop,restart,status'. (#2883)

- stop - stops all the servers.
- restart - restart all the servers.
- status - prints status of storage info about the cluster.

cmd/control-main.go

@@ -27,7 +27,7 @@ var controlCmd = cli.Command{
 	Subcommands: []cli.Command{
 		lockCmd,
 		healCmd,
-		shutdownCmd,
+		serviceCmd,
 	},
 	CustomHelpTemplate: `NAME:
    {{.Name}} - {{.Usage}}