build: Remove unnecessary std::ref, causing compilation issues with Boost 1.70.0

Refs: #4923
Change-Id: Idba1abe89161b11b1ec80fdceac51e2b00ed507b
diff --git a/daemon/face/tcp-transport.cpp b/daemon/face/tcp-transport.cpp
index 58c4add..0da07af 100644
--- a/daemon/face/tcp-transport.cpp
+++ b/daemon/face/tcp-transport.cpp
@@ -133,7 +133,13 @@
   BOOST_ASSERT(getState() == TransportState::DOWN);
 
   // recreate the socket
-  m_socket = protocol::socket(m_socket.get_io_service());
+  m_socket = protocol::socket(
+#if BOOST_VERSION >= 107000
+                              m_socket.get_executor()
+#else
+                              m_socket.get_io_service()
+#endif // BOOST_VERSION >= 107000
+                              );
   this->resetReceiveBuffer();
   this->resetSendQueue();