HDFS-7176. The namenode usage message doesn't include "-rollingupgrade started" (cmccabe)

(cherry picked from commit dd1b8f2ed8a86871517c730a9f370aca4b763514)

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

@@ -539,6 +539,9 @@ Release 2.6.0 - UNRELEASED
     HDFS-7172. Test data files may be checked out of git with incorrect line
     endings, causing test failures in TestHDFSCLI. (Chris Nauroth via wheat9)
 
+    HDFS-7176. The namenode usage message doesn't include "-rollingupgrade
+    started" (cmccabe)
+
     BREAKDOWN OF HDFS-6134 AND HADOOP-10150 SUBTASKS AND RELATED JIRAS
   
       HDFS-6387. HDFS CLI admin tool for creating & deleting an

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/NameNode.java

@@ -217,7 +217,8 @@ public class NameNode implements NameNodeStatusMXBean {
       + StartupOption.ROLLBACK.getName() + "] | \n\t["
       + StartupOption.ROLLINGUPGRADE.getName() + " <"
       + RollingUpgradeStartupOption.DOWNGRADE.name().toLowerCase() + "|"
-      + RollingUpgradeStartupOption.ROLLBACK.name().toLowerCase() + "> ] | \n\t["
+      + RollingUpgradeStartupOption.ROLLBACK.name().toLowerCase() + "|"
+      + RollingUpgradeStartupOption.STARTED.name().toLowerCase() + "> ] | \n\t["
       + StartupOption.FINALIZE.getName() + "] | \n\t["
       + StartupOption.IMPORT.getName() + "] | \n\t["
       + StartupOption.INITIALIZESHAREDEDITS.getName() + "] | \n\t["