face: make logging more uniform across channel types

Change-Id: I21db45f736e07464260dcc902c673d098ba3c549
Refs: #2561
diff --git a/daemon/face/unix-stream-channel.hpp b/daemon/face/unix-stream-channel.hpp
index 8f30db5..310030b 100644
--- a/daemon/face/unix-stream-channel.hpp
+++ b/daemon/face/unix-stream-channel.hpp
@@ -106,7 +106,7 @@
                const FaceCreationFailedCallback& onAcceptFailed);
 
 private:
-  unix_stream::Endpoint m_endpoint;
+  const unix_stream::Endpoint m_endpoint;
   boost::asio::local::stream_protocol::acceptor m_acceptor;
   boost::asio::local::stream_protocol::socket m_socket;
   size_t m_size;