Problem: no ZMQ_EVENT_HANDSHAKE_FAILED_PROTOCOL events emitted in plain_client_t

Solution: emit events at appropriate places

src/stream_engine.cpp

@@ -674,7 +674,7 @@ bool zmq::stream_engine_t::handshake ()
                     plain_server_t (session, peer_address, options);
             else
                 mechanism = new (std::nothrow)
-                    plain_client_t (options);
+                    plain_client_t (session, options);
             alloc_assert (mechanism);
         }
 #ifdef ZMQ_HAVE_CURVE