face-management-protocol: Add abstraction for FaceInstance

Change-Id: I0b8f121f3df74d88b6d8112c85552b84d076f788
diff --git a/src/node.cpp b/src/node.cpp
index 910685b..3234f18 100644
--- a/src/node.cpp
+++ b/src/node.cpp
@@ -9,6 +9,7 @@
 #include "c/util/time.h"
 
 #include <ndn-cpp/forwarding-entry.hpp>
+#include <ndn-cpp/face-instance.hpp>
 #include <ndn-cpp/node.hpp>
 
 #include "util/ndnd-id-fetcher.hpp"