HDFS-15371. Nonstandard characters exist in NameNode.java (#2032)

Contributed by zhaoyim

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

@@ -301,7 +301,7 @@ public class NameNode extends ReconfigurableBase implements
     DFS_NAMENODE_KERBEROS_PRINCIPAL_KEY,
     DFS_NAMENODE_KERBEROS_INTERNAL_SPNEGO_PRINCIPAL_KEY,
     DFS_HA_FENCE_METHODS_KEY,
-    DFS_HA_ZKFC_PORT_KEY,
+    DFS_HA_ZKFC_PORT_KEY
   };
   
   /**