fix [#34918] Interactive bevel doesn't accept +/- keys to change # of segments, only scrollwheel

Since page-up/down isnt common for this use case, replace with pad+/-


git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@55890 954f8c5b-7b00-dc11-b283-0030488c597c