Comment 3 for bug 987838

So the attached branch fixed one issue, we'll no longer get a 404 at

https://apps.ubuntu.com/cat/applications/screenshots/unity-lens-askubuntu/

but an empty list. achuni noted:

14:46 < achuni> noodles: hmmm I was going to say that extras uses a custom field on the package data
                to specify the screenshot url, but I can't remember what it was now
14:47 < noodles> achuni: ah k, I'll take a look now.
14:47 < achuni> noodles: we're currently checking the desktop file for the screenshot url, but
                extras doesn't have an app-install-data package
14:47 < achuni> noodles: so that's in the apt-cache data for extras