This is a feature of systemd and PackageKit. See http://www.freedesktop.org/wiki/Software/systemd/SystemUpdates/
The only thing which makes use of this feature is GNOME through GNOME-Software, so if you don't want this, removing GNOME-Software will be enough. Nothing else in Debian uses this[1]. Cheers, Matthias P.S: A log file on why the update failed would be very helpful though, because even if you don't use it, the functionality should be usable for those who want to use it. [1]: I know that thanks to codesearch