face: support runtime MTU changes on Ethernet faces

refs #3257

Change-Id: I160fe444b889b8f7be19022a2bd52bbc9f7a21aa
diff --git a/daemon/face/ethernet-transport.hpp b/daemon/face/ethernet-transport.hpp
index 8258285..a88b95b 100644
--- a/daemon/face/ethernet-transport.hpp
+++ b/daemon/face/ethernet-transport.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /*
- * Copyright (c) 2014-2019,  Regents of the University of California,
+ * Copyright (c) 2014-2020,  Regents of the University of California,
  *                           Arizona Board of Regents,
  *                           Colorado State University,
  *                           University Pierre & Marie Curie, Sorbonne University,
@@ -106,7 +106,8 @@
   std::string m_interfaceName;
 
 private:
-  signal::ScopedConnection m_netifStateConn;
+  signal::ScopedConnection m_netifStateChangedConn;
+  signal::ScopedConnection m_netifMtuChangedConn;
   bool m_hasRecentlyReceived;
 #ifdef _DEBUG
   /// number of frames dropped by the kernel, as reported by libpcap