Use automatic login configuration from AccountsService

Submitted by Robert Ancell @robert.ancell

Link to original bug (#791860)

Description

Created attachment 365859 Use automatic login configuration from AccountsService

As requested in https://bugs.freedesktop.org/show_bug.cgi?id=40020 display managers should pull the autologin information from AccountsService instead of configuring it themselves.

Attached patch does this. Not as AccountsService currently runs it just means that A-S now does the /etc/gdm/custom.conf read. We can separately migrate A-S to writing it's own autologin config (/var/lib/AccountsService/autologin).

The side effect of this is any other GDM configuration backend cannot configure autologin information. I'm guessing this is not an important feature and AccoutsService is always expected to be there?

Patch 365859, "Use automatic login configuration from AccountsService":
0001-Use-automatic-login-configuration-from-AccountsServi.patch