method first in trait IterableLike is deprecated: use `head' instead

streaming/src/main/scala/spark/streaming/dstream/QueueInputDStream.scala

@@ -28,7 +28,7 @@ class QueueInputDStream[T: ClassManifest](
     }
     if (buffer.size > 0) {
       if (oneAtATime) {
-        Some(buffer.first)
+        Some(buffer.head)
       } else {
         Some(new UnionRDD(ssc.sc, buffer.toSeq))
       }