Previously, gnome-screensaver would enforce a maximum to lock
and logout timeouts to prevent situations where the screen could
have locking enabled, but never lock in practice.

The screen control panel enforces a maximum of 1h, but the
GSettings schema allows arbitrarily large values. There's no
reason to have two out of sync maximums, so this commit removes
the gnome-screensaver one.

https://bugzilla.gnome.org/show_bug.cgi?id=668039