Blender Git Loki

Fix for [#26322] x-mirror gives wrong results while editing hair particles
* Tsk! Particle mirroring was working fine for the case where subsurf modifier was before particles (orcos are transformed in this case), but not the other way around (unnecessary inverse transform of orcos).
* Not really satisfied with having to check for the CD_ORIGINDEX layer, so if Brecht or somebody else knows a better way then please change this :)