aura: Fix a bug caused by commit b84d2600f0

Seems like linking with the ANSI version doesn't work on Windows.
FileStream class in StormLib was trying to open files but it couldn't
even though they were there causing an error FILE_NOT_FOUND (2). This
seriously broke the bot on probably every Windows Vista+. This commit is
a partial revert of b84d2600f0.

Thanks to user 'muzzel' who reported it.