HADOOP-16013. DecayRpcScheduler decay thread should run as a daemon. Contributed by Erik Krogen.

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/ipc/DecayRpcScheduler.java

@@ -232,7 +232,7 @@ public class DecayRpcScheduler implements RpcScheduler,
         "the number of top users for scheduler metrics must be at least 1");
 
     // Setup delay timer
-    Timer timer = new Timer();
+    Timer timer = new Timer(true);
     DecayTask task = new DecayTask(this, timer);
     timer.scheduleAtFixedRate(task, decayPeriodMillis, decayPeriodMillis);