restart/failover. Contributed by Naganarasimha G R and Xuan Gong
(cherry picked from commit 4546c7582b6762c18ba150d80a8976eb51a8290c)
Conflicts:
hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/rmapp/RMAppImpl.java
hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/rmapp/TestRMAppTransitions.java
2e2dbf59d1