Fix sculpt view normal for transformed objects

Patch from Antony Riakiotakis, thanks!

Fixes [#34641] "Front Faces Only" option in SculptMode behaves weird
projects.blender.org/tracker/?func=detail&aid=34641&group_id=9&atid=498

git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@55343 954f8c5b-7b00-dc11-b283-0030488c597c