face: override Transport::beforeChangePersistency in all subclasses

This commit also adds the final specifier to some Transport
subclasses in order to improve code generation.

Change-Id: If2979fa1614476a98019ba79cee3961663fc447b
Refs: #3318
diff --git a/daemon/face/websocket-transport.hpp b/daemon/face/websocket-transport.hpp
index 6bfbdc3..91a99c1 100644
--- a/daemon/face/websocket-transport.hpp
+++ b/daemon/face/websocket-transport.hpp
@@ -36,7 +36,7 @@
 /**
  * \brief A Transport that communicates on a WebSocket connection
  */
-class WebSocketTransport : public Transport
+class WebSocketTransport DECL_FINAL : public Transport
 {
 public:
   WebSocketTransport(websocketpp::connection_hdl hdl,
@@ -57,14 +57,14 @@
 
 protected:
   virtual void
-  beforeChangePersistency(ndn::nfd::FacePersistency newPersistency) DECL_OVERRIDE;
+  beforeChangePersistency(ndn::nfd::FacePersistency newPersistency) DECL_FINAL;
 
   virtual void
-  doClose() DECL_OVERRIDE;
+  doClose() DECL_FINAL;
 
 private:
   virtual void
-  doSend(Transport::Packet&& packet) DECL_OVERRIDE;
+  doSend(Transport::Packet&& packet) DECL_FINAL;
 
   void
   schedulePing();