Give upstream a patch so GDM can display contents of /etc/nologin

[jdreed]

New GDM is too cool for archaic things like /etc/nologin, so if that file exists, users just get a generic login failure message, and wring their hands and cry out to the gods in frustration, cursing the GNOME developer who would impose such cruelty on the world.

There is an upstream bug, but probably nothing is going to happen until someone actually sends them a patch. So, someone should do that, and then we can get rid of stupid things like debathena-nologin-monitor.

[jdreed]

geofft notes that it's possible that this is a PAM bug.