Remove MotionPathEffect

As resolved here:
http://lists.w3.org/Archives/Public/public-fx/2014OctDec/0009.html

Generated from:

commit e0e116e31960033beccc67b9a5047cfcb0b0f92a
Author: Brian Birtles <birtles@gmail.com>
Date:   Wed Nov 19 16:35:45 2014 +0900

    Remove MotionPathEffect

    As resolved here:
    http://lists.w3.org/Archives/Public/public-fx/2014OctDec/0009.html