face-management-protocol: Add abstraction for FaceInstance

Change-Id: I0b8f121f3df74d88b6d8112c85552b84d076f788
diff --git a/include/ndn-cpp/forwarding-entry.hpp b/include/ndn-cpp/forwarding-entry.hpp
index 315f271..662409a 100644
--- a/include/ndn-cpp/forwarding-entry.hpp
+++ b/include/ndn-cpp/forwarding-entry.hpp
@@ -8,6 +8,7 @@
 #ifndef NDN_FORWARDING_ENTRY_HPP
 #define NDN_FORWARDING_ENTRY_HPP
 
+#include "encoding/tlv-face-management.hpp"
 #include "name.hpp"
 #include "forwarding-flags.hpp"
 #include "encoding/block.hpp"