criterion update: add "switch user" to Shutdown, reboot, logout

[Kevin Kofler]

Matthias Clasen wrote:
> Testing it is fine of course, but I don't really think we should block
> on this. Also worth considering: user switching has never worked 100%
> reliably, so increased qa focus may just uncover old heisenbugs, and
> turn them into blocking issues.

Maybe for GNOME it hasn't. For KDE, using KDM or SDDM, user switching has 
always just worked. Nowadays, it should just work with GDM too, but of 
course it can be subject to bugs and undocumented behavior changes in GDM 
(which wouldn't be a first).

IMHO, adding user switching to the blocker criteria is a good idea. Bugs in 
user switching can easily lead to data loss, either directly (e.g., if user 
switching crashes the machine) or indirectly (e.g., if, due to user 
switching not working, somebody just logs the other account off without 
caring about running processes, or even hits the power or reset button if 
the session is locked).

        Kevin Kofler