Fix bounding boxes after rP25306
Skinning calculations must happen in bone-space.
Fixes rP25306
Reported by: langbart
Fixes #6168
Differential Revision: https://code.wildfiregames.com/D3927
@wraitii I tested D3927 with diff id 17396, when testing the latest SVN version the problem is back, it seems a later iteration of the patch brought back the problem.
I have tested rP25391 and it solves the problem.