Reverting commit 1d431190

The patch was supposed to check that pipe writer sends messages
in atomic fashion. However, it prevented the user to read
half of a message and close the socket.
Signed-off-by: Martin Sustrik <sustrik@250bpm.com>

src/xrep.cpp

@@ -101,13 +101,6 @@ void zmq::xrep_t::terminated (reader_t *pipe_)
     for (inpipes_t::iterator it = inpipes.begin (); it != inpipes.end ();
           it++) {
         if (it->reader == pipe_) {
-            if (inpipes [current_in].reader == pipe_) {
-
-                //  A reader is not allowed to terminate in the middle of a
-                //  multipart message.
-                zmq_assert (!prefetched);
-                zmq_assert (!more_in);
-            }
             inpipes.erase (it);
             if (terminating)
                 unregister_term_ack ();