Minor code clean-up to keep clang compiler happy.

"warning: extra ';' inside a struct or union [-pedantic]"
Signed-off-by: Martin Sustrik <sustrik@250bpm.com>

src/pipe.hpp

@@ -48,7 +48,7 @@ namespace zmq
 
     struct i_reader_events
     {
-        virtual ~i_reader_events () {};
+        virtual ~i_reader_events () {}
 
         virtual void terminated (class reader_t *pipe_) = 0;
         virtual void activated (class reader_t *pipe_) = 0;
@@ -118,7 +118,7 @@ namespace zmq
 
     struct i_writer_events
     {
-        virtual ~i_writer_events () {};
+        virtual ~i_writer_events () {}
 
         virtual void terminated (class writer_t *pipe_) = 0;
         virtual void activated (class writer_t *pipe_) = 0;