face: Implementation of encode/decode of LocalControlHeader

LocalControlHeader can only be used on faces that are derived from
LocalFace.  UnixStreamFace is directly inherited from LocalFace,
TCP face has two specializations: generic TcpFace (strictly not local),
and LocalTcpFace.

refs #1213

Change-Id: I8a158c3bc4bb929eedd15757cfddecc0d1049f9f
diff --git a/daemon/face/unix-stream-face.hpp b/daemon/face/unix-stream-face.hpp
index cc97c21..8492f54 100644
--- a/daemon/face/unix-stream-face.hpp
+++ b/daemon/face/unix-stream-face.hpp
@@ -20,20 +20,13 @@
  * \brief Implementation of Face abstraction that uses stream-oriented
  *        Unix domain sockets as underlying transport mechanism
  */
-class UnixStreamFace : public StreamFace<boost::asio::local::stream_protocol>
+class UnixStreamFace : public StreamFace<boost::asio::local::stream_protocol, LocalFace>
 {
 public:
   typedef boost::asio::local::stream_protocol protocol;
 
   explicit
   UnixStreamFace(const shared_ptr<protocol::socket>& socket);
-
-  /** \brief Get whether face is connected to a local app
-   *
-   *  Always true for a UnixStreamFace.
-   */
-  virtual bool
-  isLocal() const;
 };
 
 } // namespace nfd