Update postinst file to follow v2 security elements

Change-Id: I17e11e05043ba864052419604096e72a6238ec9c
diff --git a/nfd/Makefile b/nfd/Makefile
index ebe0cfd..6f8f4c6 100644
--- a/nfd/Makefile
+++ b/nfd/Makefile
@@ -11,6 +11,6 @@
 VERSION=0.6.0-29-g3d2049fb
 
 # PPA version
-PPA_VERSION=1
+PPA_VERSION=2
 
 include ../packaging.mk