Removed unncessary options from WindowedDStream.

streaming/src/main/scala/org/apache/spark/streaming/dstream/WindowedDStream.scala

@@ -39,8 +39,6 @@ class WindowedDStream[T: ClassTag](
     throw new Exception("The slide duration of WindowedDStream (" + _slideDuration + ") " +
     "must be multiple of the slide duration of parent DStream (" + parent.slideDuration + ")")
 
-  val useNewUnion = System.getProperty("spark.streaming.useNewUnion", "true").toBoolean
-
   parent.persist(StorageLevel.MEMORY_ONLY_SER)
 
   def windowDuration: Duration =  _windowDuration
@@ -54,11 +52,11 @@ class WindowedDStream[T: ClassTag](
   override def compute(validTime: Time): Option[RDD[T]] = {
     val currentWindow = new Interval(validTime - windowDuration + parent.slideDuration, validTime)
     val rddsInWindow = parent.slice(currentWindow)
-    val windowRDD = if (useNewUnion && rddsInWindow.flatMap(_.partitioner).distinct.length == 1) {
-      logInfo("Using partition aware union")
+    val windowRDD = if (rddsInWindow.flatMap(_.partitioner).distinct.length == 1) {
+      logDebug("Using partition aware union for windowing at " + validTime)
       new PartitionerAwareUnionRDD(ssc.sc, rddsInWindow)
     } else {
-      logInfo("Using normal union")
+      logDebug("Using normal union for windowing at " + validTime)
       new UnionRDD(ssc.sc,rddsInWindow)
     }
     Some(windowRDD)