KeyValues::LoadFromFile seems to ignore overridden files

[TorutheRedFox]

KeyValues::LoadFromFile doesn't seem to be loading a custom version of GameMenu.res that I put in to the files for the TF2 SDK, both from the custom folder and as a loose file

Modifying the code to make it read a differently named file works just fine, but for some reason, leaving it as-is makes the original file take priority.