Merge pull request #427 from ianbarber/master

Init msg in pgm_receiver drop subs

src/pgm_receiver.cpp

@@ -274,6 +274,7 @@ void zmq::pgm_receiver_t::timer_event (int token)
 void zmq::pgm_receiver_t::drop_subscriptions ()
 {
     msg_t msg;
+    msg.init ();
     while (session->pull_msg (&msg))
         msg.close ();
 }