Removing extra code in new yarn

new-yarn/src/main/scala/org/apache/spark/deploy/yarn/WorkerLauncher.scala

@@ -59,7 +59,6 @@ class WorkerLauncher(args: ApplicationMasterArguments, conf: Configuration) exte
     override def preStart() {
       logInfo("Listen to driver: " + driverUrl)
       driver = context.actorFor(driverUrl)
-      driver ! "hello"
       context.system.eventStream.subscribe(self, classOf[RemotingLifecycleEvent])
     }