fix [#35648] Loop cut, smoothness showing wrong symmetrical

this is more of a feature request then a bug, but nicer to use even smoothing offset for loopcut smoothing.


git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@57331 954f8c5b-7b00-dc11-b283-0030488c597c