[SPARK-19137][SQL][SS] Garbage left in source tree after SQL tests are run

Author: dongjoon-hyun

sql/core/src/test/scala/org/apache/spark/sql/streaming/test/DataStreamReaderWriterSuite.scala

@@ -601,9 +601,11 @@ class DataStreamReaderWriterSuite extends StreamTest with BeforeAndAfter with Pr
         StructField("part", IntegerType), // inferred partitionColumn dataType
         StructField("id", StringType))) // used user provided partitionColumn dataType
 
+      val checkpointLoc = newMetadataDir
       val sq = sdf.writeStream
         .queryName("corruption_test")
         .format("memory")
+        .option("checkpointLocation", checkpointLoc)
         .start()
       sq.processAllAvailable()
       checkAnswer(