Merge branch 'master' into SPARK-4924

Author: Marcelo Vanzin

core/src/main/scala/org/apache/spark/storage/DiskBlockManager.scala

@@ -166,7 +166,7 @@ private[spark] class DiskBlockManager(blockManager: BlockManager, conf: SparkCon
   /** Cleanup local dirs and stop shuffle sender. */
   private[spark] def stop() {
     // Only perform cleanup if an external service is not serving our shuffle files.
-    if (!blockManager.externalShuffleServiceEnabled) {
+    if (!blockManager.externalShuffleServiceEnabled || blockManager.blockManagerId.isDriver) {
       localDirs.foreach { localDir =>
         if (localDir.isDirectory() && localDir.exists()) {
           try {