HDFS-15608.Reset the DistCp#CLEANUP variable definition. (#2351). Contributed by JiangHua Zhu.

Co-authored-by: zhujianghua <zhujianghua@zhujianghuadeMacBook-Pro.local>

hadoop-tools/hadoop-distcp/src/main/java/org/apache/hadoop/tools/DistCp.java

@@ -445,9 +445,9 @@ public class DistCp extends Configured implements Tool {
     int exitCode;
     try {
       DistCp distCp = new DistCp();
-      Cleanup CLEANUP = new Cleanup(distCp);
+      Cleanup cleanup = new Cleanup(distCp);
 
-      ShutdownHookManager.get().addShutdownHook(CLEANUP,
+      ShutdownHookManager.get().addShutdownHook(cleanup,
         SHUTDOWN_HOOK_PRIORITY);
       exitCode = ToolRunner.run(getDefaultConf(), distCp, argv);
     }