Comment 5 for bug 1349368

Basically what installing qt5-default does is symlink /usr/lib/x86_64-linux-gnu/qtchooser/qt5.conf to default.conf. Notice that qmlscene is actually a symlink to qtchooser, and it's the chooser's fault to be choosing a non-installed version of qmlscene.

Anyway, there're a few ways we could work around this, but the easiest to implement is depending on qt5-default. I don't like installing 60 MB of unneeded development packages, but it will be the fastest way to get certification working.

I'll amend the merge in a moment.