Server side rendering of flot pie charts broken

Line 180 of jquery.flot.pie.js says:
    target = $(canvas).parent();

But there is no parent for the node-canvas, so it fails and subsequently all pie rendering fails.

Not sure of the solution for this. If we were using jsdom this likely wouldn't be an issue.. I guess the alternative is to modify the pie library? 

Does learnboost use the rgraph pie chart to get around this?
