build: switch to C++17

Change-Id: Ie68020a04b7e20b74778b6d0370544ded55c5e26
diff --git a/daemon/face/websocket-channel.cpp b/daemon/face/websocket-channel.cpp
index 957c9ad..2ee41cd 100644
--- a/daemon/face/websocket-channel.cpp
+++ b/daemon/face/websocket-channel.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /*
- * Copyright (c) 2014-2021,  Regents of the University of California,
+ * Copyright (c) 2014-2022,  Regents of the University of California,
  *                           Arizona Board of Regents,
  *                           Colorado State University,
  *                           University Pierre & Marie Curie, Sorbonne University,
@@ -126,7 +126,7 @@
   auto linkService = make_unique<GenericLinkService>();
   auto transport = make_unique<WebSocketTransport>(hdl, m_server, m_pingInterval);
   auto face = make_shared<Face>(std::move(linkService), std::move(transport));
-  face->setChannel(shared_from_this()); // use weak_from_this() in C++17
+  face->setChannel(weak_from_this());
 
   BOOST_ASSERT(m_channelFaces.count(hdl) == 0);
   m_channelFaces[hdl] = face;