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/tcp-transport.hpp b/daemon/face/tcp-transport.hpp
index 654f224..b2d9fcf 100644
--- a/daemon/face/tcp-transport.hpp
+++ b/daemon/face/tcp-transport.hpp
@@ -33,7 +33,7 @@
 /**
  * \brief A Transport that communicates on a connected TCP socket
  */
-class TcpTransport : public StreamTransport<boost::asio::ip::tcp>
+class TcpTransport DECL_FINAL : public StreamTransport<boost::asio::ip::tcp>
 {
 public:
   TcpTransport(protocol::socket&& socket,
@@ -41,7 +41,7 @@
 
 protected:
   virtual void
-  beforeChangePersistency(ndn::nfd::FacePersistency newPersistency) DECL_OVERRIDE;
+  beforeChangePersistency(ndn::nfd::FacePersistency newPersistency) DECL_FINAL;
 };
 
 } // namespace face