Revert "Fix start-slave not passing instance number to spark-daemon."

This reverts commit a674d67c.

bin/start-slave.sh

@@ -12,4 +12,4 @@ if [ "$SPARK_PUBLIC_DNS" = "" ]; then
     fi
 fi
 
-"$bin"/spark-daemon.sh start spark.deploy.worker.Worker 1 "$@"
+"$bin"/spark-daemon.sh start spark.deploy.worker.Worker "$@"