Fixing "batches.h" header inclusions.

closes #11
diff --git a/utils/batches.cc b/utils/batches.cc
index 1dbccfa..6292b50 100644
--- a/utils/batches.cc
+++ b/utils/batches.cc
@@ -18,7 +18,7 @@
  * Author: Alexander Afanasyev <alexander.afanasyev@ucla.edu>
  */
 
-#include "ns3/batches.h"
+#include "batches.h"
 
 namespace ns3 {