fix for weight paint using values over 1.0 when blending,
since its possible to have a brush strength over 1.0, it was possible to paint weights which would over-shoot the intended weight.


git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@54833 954f8c5b-7b00-dc11-b283-0030488c597c