repo-ng: Update to ndn-cxx 0.5.1

Change-Id: Ic76c591007d6c4d4dd4df00261da9c5fe02e6c8f
diff --git a/repo-ng/Makefile b/repo-ng/Makefile
index 475edf0..27cb063 100644
--- a/repo-ng/Makefile
+++ b/repo-ng/Makefile
@@ -11,6 +11,6 @@
 VERSION=0.0.10
 
 # PPA version
-PPA_VERSION=1
+PPA_VERSION=2
 
 include ../packaging.mk