Gfx toSVG fix for pie chart on IE8

toSVG is broken on IE8 for pie charts (works fine for other types of charts), minimal example - https://gist.github.com/alexkasko/f42618dc5077944be5d6

For some reason `object.shape` has no `type` attribute for pie chart slices in `utils.js#deserialize` so `parent.createShape(...)` returns `null` for the slices. Workaround is to check for `null` result and create path directly.

Note, the problem is not related to cross-domain/iframe as the full dojo is served from the same server.

Error on IE8:

    Webpage error details

    User Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1; WOW64; Trident/4.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0)
    Timestamp: Wed, 26 Nov 2014 10:42:39 UTC


    Message: 'null' is null or not an object
    Line: 1
    Char: 1
    Code: 0
    URI: http://192.168.42.2:8000/dojo-latest/dojox/gfx/resources/gfxSvgProxyFrame.html