[SPARK-4694]Fix HiveThriftServer2 cann't stop In Yarn HA mode.

HiveThriftServer2 can not exit automactic when changing the standy resource manager in Yarn HA mode.
The scheduler backend was aware of the AM had been exited so it call sc.stop to exit the driver process but there was a user thread(HiveThriftServer2 ) which was still alive and cause this problem.
To fix it, make a demo thread to detect the sparkContext is null or not.If the sc is stopped, call the ThriftServer.stop to stop the user thread.

Author: carlmartin <carlmartinmax@gmail.com>

Closes #3576 from SaintBacchus/ThriftServer2ExitBug and squashes the following commits:

2890b4a [carlmartin] Use SparkListener instead of the demo thread to stop the hive server.
c15da0e [carlmartin] HiveThriftServer2 can not exit automactic when changing the standy resource manager in Yarn HA mode

sql/hive-thriftserver/src/main/scala/org/apache/spark/sql/hive/thriftserver/HiveThriftServer2.scala

@@ -27,6 +27,7 @@ import org.apache.spark.Logging
 import org.apache.spark.annotation.DeveloperApi
 import org.apache.spark.sql.hive.HiveContext
 import org.apache.spark.sql.hive.thriftserver.ReflectionUtils._
+import org.apache.spark.scheduler.{SparkListenerApplicationEnd, SparkListener}
 
 /**
  * The main entry point for the Spark SQL port of HiveServer2.  Starts up a `SparkSQLContext` and a
@@ -44,9 +45,9 @@ object HiveThriftServer2 extends Logging {
     val server = new HiveThriftServer2(sqlContext)
     server.init(sqlContext.hiveconf)
     server.start()
+    sqlContext.sparkContext.addSparkListener(new HiveThriftServer2Listener(server))
   }
 
-
   def main(args: Array[String]) {
     val optionsProcessor = new ServerOptionsProcessor("HiveThriftServer2")
     if (!optionsProcessor.process(args)) {
@@ -69,12 +70,23 @@ object HiveThriftServer2 extends Logging {
       server.init(SparkSQLEnv.hiveContext.hiveconf)
       server.start()
       logInfo("HiveThriftServer2 started")
+      SparkSQLEnv.sparkContext.addSparkListener(new HiveThriftServer2Listener(server))
     } catch {
       case e: Exception =>
         logError("Error starting HiveThriftServer2", e)
         System.exit(-1)
     }
   }
+
+  /**
+   * A inner sparkListener called in sc.stop to clean up the HiveThriftServer2
+   */
+  class HiveThriftServer2Listener(val server: HiveServer2) extends SparkListener {
+    override def onApplicationEnd(applicationEnd: SparkListenerApplicationEnd): Unit = {
+      server.stop()
+    }
+  }
+
 }
 
 private[hive] class HiveThriftServer2(hiveContext: HiveContext)