fix: set correctly request->session

The session cookie was not created because request->session pointed at
a temporary session.

While here:
- do some cleaning in App
- set request->mount too
- add fcgi_cannot_create_request_delay to the config
- fix: in mailregister plugin get model_connector from env (and not from the request)

winixd/plugins/mailregister/init.cpp

@@ -123,9 +123,7 @@ void ConfigReload(PluginInfo & info)
 //		iq.SetAll(true, false);
 //		iq.WhereParentId(dir->id);
 
-		// CHECKME is it correct to get connector from the last item?
-		morm::ModelConnector * model_connector = info.cur->request->last_item->get_connector();
-		morm::Finder<Item> finder(model_connector);
+		morm::Finder<Item> finder(info.model_connector);
 
 		finder.
 			select().