hotspot: fix double free between hostpot and knownnetworks

The module framework was changed to call the module exit functions in
the reverse order as the init functions. This uncovered/caused known
networks to try and free the network_info structures after hotspot had
already freed them. Since known networks clean up the network_info's
anyways, we don't actually need hotspot to do any cleanup.

src/hotspot.c

@@ -524,7 +524,7 @@ static void hotspot_exit(void)
 {
 	l_dir_watch_destroy(hs20_dir_watch);
 
-	l_queue_destroy(hs20_settings, hs20_config_free);
+	l_queue_destroy(hs20_settings, NULL);
 	hs20_settings = NULL;
 }