Require admin password to shutdown/restart while other users are logged in.

[gauravjuvekar]

@clefebvre

MDM allows shutdown while other users are logged in without admin/root password. This allows someone to shutdown the system by lock screen --> switch user--> shutdown from mdm

[clefebvre]

I'm not sure what to think about this... last year we reduced the scope of MDM to be a local DM. So in most use cases we can assume whoever is in front of the login screen is also in front of the computer, and therefore able to press the physical shutdown button.

It's worth a design discussion, on IRC maybe. Closing the issue for now.