face: Implementing forgotten isListening() feature in TcpChannel

Change-Id: Idfcd8337d16b414d2f739f936660dffdce413729
diff --git a/daemon/face/tcp-channel.hpp b/daemon/face/tcp-channel.hpp
index 3c56cb1..e31723b 100644
--- a/daemon/face/tcp-channel.hpp
+++ b/daemon/face/tcp-channel.hpp
@@ -85,6 +85,9 @@
   size_t
   size() const;
 
+  bool
+  isListening() const;
+
 private:
   void
   createFace(const shared_ptr<boost::asio::ip::tcp::socket>& socket,
@@ -128,10 +131,16 @@
   typedef std::map< tcp::Endpoint, shared_ptr<Face> > ChannelFaceMap;
   ChannelFaceMap m_channelFaces;
 
-  bool isListening;
+  bool m_isListening;
   shared_ptr<boost::asio::ip::tcp::acceptor> m_acceptor;
 };
 
+inline bool
+TcpChannel::isListening() const
+{
+  return m_isListening;
+}
+
 } // namespace nfd
 
 #endif // NFD_FACE_TCP_CHANNEL_HPP