Tar.bz2 download gives empty file

[jasonkliu]

Repro steps:

1. Go to any Chromium code review, e.g. https://codereview.chromium.org/2339253002/
2. Click Download [tar.bz2]

This gives an empty file, and seems to do so for most Chromium code reviews that I've tried.
It doesn't seem to do the same for others, such as this: https://codereview.appspot.com/307630043/

Perhaps upgrading the Chromium rietveld version would fix this?