gupnp-simple-igd-thread: Avoid re-entrant dispose into GUPnP
gupnp-simple-igd-thread: Avoid re-entrant dispose into GUPnP

It seems that GUPnP is really unhappy if you dispose it's objects from re-entrant
calls. So instead, just wait for the main loop to exit to do the actual disposal.

GNOME/gupnp-igd