Comment 1 for bug 827898

This is a decision of the greeter. So we have a few greeters to fix:
- The GTK+ and Qt greeters that come with LightDM - should have the same behaviour
- Unity Greeter - The design asks for the last logged in user to be selected

I think the default greeters should also use the "last logged in" priority.

For comparison, GDM ordered users by frequency of login (which was confusing as the order changed all the time).