SVG markup of (malformed) pie chart is incorrect

This bug does not produce any visible errors but produces malformed SVG markup and forces Chrome to throw an error for every occurrence, which in my case is a lot.
It may be reproducible on all webkit based browsers but i have only Chrome to test this on.

Fixes trac [#2532710](http://yuilibrary.com/projects/yui3/ticket/2532710)