HDFS-8579. Update HDFS usage with missing options (Contributed by J.Andreina)

(cherry picked from commit 77588e1d32cc465e6b0699bb3564a4c7c6df16fa)

Conflicts:
	hadoop-hdfs-project/hadoop-hdfs/src/main/bin/hdfs

hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt

@@ -650,6 +650,9 @@ Release 2.8.0 - UNRELEASED
     HDFS-8687. Remove the duplicate usage message from Dfsck.java. (Brahma
     Reddy Battula via Arpit Agarwal)
 
+    HDFS-8579. Update HDFS usage with missing options
+    (J.Andreina via vinayakumarb)
+
 Release 2.7.2 - UNRELEASED
 
   INCOMPATIBLE CHANGES

hadoop-hdfs-project/hadoop-hdfs/src/main/bin/hdfs

@@ -45,6 +45,7 @@ function print_usage(){
   echo "  journalnode          run the DFS journalnode"
   echo "  zkfc                 run the ZK Failover Controller daemon"
   echo "  datanode             run a DFS datanode"
+  echo "  debug                run a Debug Admin to execute HDFS debug commands"
   echo "  dfsadmin             run a DFS admin client"
   echo "  haadmin              run a DFS HA admin client"
   echo "  fsck                 run a DFS filesystem checking utility"