face: Transport::canChangePersistencyTo

Feasibility of transport persistency change can be checked with
Transport::canChangePersistencyTo before executing the actual change.
This enables management to verify persistency and other parameters
in a faces/update command before applying the updates.

Change-Id: Ia283f0daf678f47aad7b78b7e06dee4827f57cab
refs: #3232
diff --git a/daemon/face/multicast-udp-transport.hpp b/daemon/face/multicast-udp-transport.hpp
index b16ac6a..2b04eb7 100644
--- a/daemon/face/multicast-udp-transport.hpp
+++ b/daemon/face/multicast-udp-transport.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /**
- * Copyright (c) 2014-2016,  Regents of the University of California,
+ * Copyright (c) 2014-2017,  Regents of the University of California,
  *                           Arizona Board of Regents,
  *                           Colorado State University,
  *                           University Pierre & Marie Curie, Sorbonne University,
@@ -57,15 +57,11 @@
                         protocol::socket&& recvSocket,
                         protocol::socket&& sendSocket);
 
-protected:
-  virtual void
-  beforeChangePersistency(ndn::nfd::FacePersistency newPersistency) final;
-
 private:
-  virtual void
+  void
   doSend(Transport::Packet&& packet) final;
 
-  virtual void
+  void
   doClose() final;
 
 private: