helper: Fixing unused variable warning
diff --git a/helper/ndn-global-routing-helper.cc b/helper/ndn-global-routing-helper.cc
index 44354d4..122bffb 100644
--- a/helper/ndn-global-routing-helper.cc
+++ b/helper/ndn-global-routing-helper.cc
@@ -325,8 +325,6 @@
    * See http://www.boost.org/doc/libs/1_49_0/libs/graph/doc/table_of_contents.html for more details
    */
 
-  int counter = 0;
-
   BOOST_CONCEPT_ASSERT(( VertexListGraphConcept< NdnGlobalRouterGraph > ));
   BOOST_CONCEPT_ASSERT(( IncidenceGraphConcept< NdnGlobalRouterGraph > ));