Code review comment for lp:~mvo/software-center/lp914393

Please note that the root of this crash is hopefully addressed with my patch for gtk+ in
https://bugs.launchpad.net/ubuntu/+source/apport/+bug/938090/comments/11
but even with that we should still merge this branch to avoid getting hit by similar problems
(and because AFAICT there is no reason to exit right away).