face: internal KeyChain

refs #2039

This commit deprecates:

* nfd::Controller::Controller(Face&)

Change-Id: Iecc60c45ba6134dbcc34f58dcdf6a171e7b05253
diff --git a/src/detail/face-impl.hpp b/src/detail/face-impl.hpp
index 155185d..eb286d7 100644
--- a/src/detail/face-impl.hpp
+++ b/src/detail/face-impl.hpp
@@ -217,7 +217,7 @@
     }
 
     RegisteredPrefix::Unregistrator bindedUnregistrator =
-        ndn::bind(unregistrator, m_face.m_nfdController.get(), unregisterParameters, _1, _2,
+        ndn::bind(unregistrator, m_face.m_nfdController, unregisterParameters, _1, _2,
                   signatureGenerator,
                   m_face.m_nfdController->getDefaultCommandTimeout());