HDFS-9871. "Bytes Being Moved" -ve(-1 B) when cluster was already balanced. (Contributed by Brahma Reddy Battulla)

(cherry picked from commit 1f004b3367c57de9e8a67040a57efc31c9ba8ee2)

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/balancer/Balancer.java

@@ -578,7 +578,7 @@ public class Balancer {
       final long bytesLeftToMove = init(reports);
       if (bytesLeftToMove == 0) {
         System.out.println("The cluster is balanced. Exiting...");
-        return newResult(ExitStatus.SUCCESS, bytesLeftToMove, -1);
+        return newResult(ExitStatus.SUCCESS, bytesLeftToMove, 0);
       } else {
         LOG.info( "Need to move "+ StringUtils.byteDesc(bytesLeftToMove)
             + " to make the cluster balanced." );