**breaking change**: Switch Face and related classes to v2::KeyChain

security::v2::KeyChain is now exposed as ndn::KeyChain, which should
ensure that dependent code can be mostly compiled.  However, expect code
that explicitly uses the old KeyChain interface to be broken.

Change-Id: I7330d0250d92f3f0f2570ab6d0214ab3dfdd18cc
Refs: #3098
diff --git a/src/util/notification-stream.hpp b/src/util/notification-stream.hpp
index 212f7e5..1c7887e 100644
--- a/src/util/notification-stream.hpp
+++ b/src/util/notification-stream.hpp
@@ -30,7 +30,7 @@
 
 #include "../name.hpp"
 #include "../face.hpp"
-#include "../security/v1/key-chain.hpp"
+#include "../security/v2/key-chain.hpp"
 
 #include "concepts.hpp"