If you select a game that isn't currently supported
(say, an engine isn't currently compiled) and try to
play it, the configuration domain is set but,
naturally, the engine fails to launch and you return to
the launcher.
If you now try to quit the launcher, the domain is
still set and main again tries to launch the engine,
fails, and returns you to the launcher. Repeat ad
infinitum.
The main loop could either react to the return value of
the launcher (which isn't currently used) or the
launcher could clear the domain. Or both. Patch makes
launcher clear the domain when quit is selected.
Ticket imported from: #1503715. Ticket imported from: bugs/2660.
Patch to make launcher clear domain in case of quit.