src: drop 'virtual' from functions marked 'final' or 'override'

Change-Id: Ieb6df864ab82f77b2bee9e83aa0bfa2005715950
Refs: #3857
diff --git a/src/util/dummy-client-face.cpp b/src/util/dummy-client-face.cpp
index 911d3bb..f6150b3 100644
--- a/src/util/dummy-client-face.cpp
+++ b/src/util/dummy-client-face.cpp
@@ -43,28 +43,28 @@
     }
   }
 
-  virtual void
+  void
   close() override
   {
   }
 
-  virtual void
+  void
   pause() override
   {
   }
 
-  virtual void
+  void
   resume() override
   {
   }
 
-  virtual void
+  void
   send(const Block& wire) override
   {
     onSendBlock(wire);
   }
 
-  virtual void
+  void
   send(const Block& header, const Block& payload) override
   {
     EncodingBuffer encoder(header.size() + payload.size(), header.size() + payload.size());