Upgrade underlying NFD/ndn-cxx to version 0.6.5

Change-Id: If83629472f737c017bbd9109fe814a5d5ecc44d4
diff --git a/.gitmodules b/.gitmodules
index fb3347b..e250871 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -1,8 +1,8 @@
 [submodule "NFD"]
 	path = NFD
 	url = https://github.com/named-data-ndnSIM/NFD
-	branch = NFD-0.6.1-ndnSIM
+	branch = NFD-0.6.5-ndnSIM
 [submodule "ndn-cxx"]
 	path = ndn-cxx
 	url = https://github.com/named-data-ndnSIM/ndn-cxx
-	branch = ndn-cxx-0.6.1-ndnSIM
+	branch = ndn-cxx-0.6.5-ndnSIM