Game shouldn't crash when system folders are unavailable.

[Stan]

As reported here:

​https://wildfiregames.com/forum/index.php?/topic/24426-0ad-wont-run-at-work/

Game should fall back to -writableroot behavior when it can't write to system directories instead of crashing.

[Vladislav Belov]

The auto fallback seems misleading. We need to notify players, what's going on. Also what should we do, when the original access is restored? Copy files? Because you will have a duplicated data. It seems pretty complex for the game.

I think the user should control this step, we only notify him. As leper said, we don't need to manage everything. Because the same thing may happen, if the data folder is mounted separately.

[Stan]

Well then not crashing would be nice :)