Comment 7 for bug 871450

Hi John,

Here is an updated version of this patch that fixes the case where there is no json library. It's actually a bit obsolete since I've changed our build to make sure it can find one, but since this was mostly done I thought I might as well send it.

I'm not 100% sure the fix is covering what you intend for the test to do but I think it's correct.

By the way, people here are finding meliae really useful for Python memory problems - thanks!