security: Fix the compile problem caused by an API change of ValidatorConfig.

Refs: #1481

Change-Id: Iea5cb1e13b509d570d8eb6b05ccb3fd6d7816bbc
diff --git a/rib/rib-manager.hpp b/rib/rib-manager.hpp
index 40b5818..44299e6 100644
--- a/rib/rib-manager.hpp
+++ b/rib/rib-manager.hpp
@@ -117,7 +117,7 @@
 
 private:
   Rib m_managedRib;
-  ndn::shared_ptr<ndn::Face> m_face;
+  ndn::Face m_face;
   ndn::shared_ptr<ndn::nfd::Controller> m_nfdController;
   ndn::KeyChain m_keyChain;
   ndn::ValidatorConfig m_validator;