HDFS-13799. TestEditLogTailer#testTriggersLogRollsForAllStandbyNN fails due to missing synchronization

            between rollEditsRpcExecutor and tailerThread shutdown. Contributed by Hrishikesh Gadre.

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

@@ -234,7 +234,6 @@ public class EditLogTailer {
   }
   
   public void stop() throws IOException {
-    rollEditsRpcExecutor.shutdown();
     tailerThread.setShouldRun(false);
     tailerThread.interrupt();
     try {
@@ -242,6 +241,8 @@ public class EditLogTailer {
     } catch (InterruptedException e) {
       LOG.warn("Edit log tailer thread exited with an exception");
       throw new IOException(e);
+    } finally {
+      rollEditsRpcExecutor.shutdown();
     }
   }