[FFe] Report hw submission on upgrade

We decided to not show up gnome-initial-setup after upgrade during first relogin. Consequently, we need to report automatically submission on upgrade to ensure our current hw submission and upgrade information per distro matches our user base.

Note that the gnome-initial-setup dialog was stating that we do regular submissions and enabled to show the first report.

Basically, the design is:
- having a xdg autostart service starting on user session. Unfortunately, as the start condition is dependent on a file including the release name, we can't prevent this small service starting or we would need a package rebuild at every release, which my trigger issues if we forget in the future.
- we check if we already reported for this release and exit as early as possible
- if there was no previous report -> new install -> exit as well (and let g-i-s dialog presenting it)
- otherwise, check previous report content for opt-out/opt-in marker. If opt-out, send again an opt-out message for new release, if opt-in, collect again and send new/updated hw and upgrade information.

The code is isolated from the rest (new functions, isolated code, hidden in the helper for people to not trigger it inadvertently), and heavily tested.

Here is a ppa build of the package: https://launchpad.net/~didrocks/+archive/ubuntu/ppa/+build/15492474