Addendum patch for YARN-6102.

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/ResourceManager.java

@@ -1313,7 +1313,6 @@ public class ResourceManager extends CompositeService implements Recoverable {
     rmContextImpl.setDispatcher(dispatcher);
 
     rmContext = rmContextImpl;
-    rmContext.setDispatcher(rmDispatcher);
   }
 
   private void setSchedulerRecoveryStartAndWaitTime(RMState state,