Merge pull request #1894 from hitstergtd/libzmq-docfixes-1

Fix typo

src/ypipe.hpp

@@ -61,7 +61,7 @@ namespace zmq
             c.set (&queue.back ());
         }
 
-        //  The destructor doesn't have to be virtual. It is mad virtual
+        //  The destructor doesn't have to be virtual. It is made virtual
         //  just to keep ICC and code checking tools from complaining.
         inline virtual ~ypipe_t ()
         {