YARN-6304. Skip rm.transitionToActive call to RM if RM is already active. Contributed by Rohith Sharma K S.

(cherry picked from commit 6ed9d362242d36bfae4083bf3b1c2eb32fbb2f72)
(cherry picked from commit 9289f4527d8fc3418fdeb8bf213b0f62525092d5)

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

@@ -288,6 +288,9 @@ public class AdminService extends CompositeService implements
   @Override
   public synchronized void transitionToActive(
       HAServiceProtocol.StateChangeRequestInfo reqInfo) throws IOException {
+    if (isRMActive()) {
+      return;
+    }
     // call refreshAdminAcls before HA state transition
     // for the case that adminAcls have been updated in previous active RM
     try {