connector: Fallback on the socket output callback

Fixes T124

Signed-off-by: David Wedderwille <davidwe@posteo.de>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>

src/server.c

@@ -314,6 +314,7 @@ static void ssh_server_connection_callback(ssh_session session){
 
             /* from now, the packet layer is handling incoming packets */
             session->socket_callbacks.data=ssh_packet_socket_callback;
+            ssh_packet_register_socket_callback(session, session->socket);
 
             ssh_packet_set_default_callbacks(session);
             set_status(session, 0.5f);