bug#43392: utmp file not correctly updated when logging out from xfce to sddm

[Jesse Gibbons]

To replicate:

From a fresh startup,

1. log in to the XFCE window manager from the SDDM display manager.

2. log out

3. In a virtual console, log in with the same user and run `who`

Expected results:

The value of $USER should be listed once, because it is officially 
logged in only once.

Actual results:

The value of $USER is listed twice, and one of them is not associated 
with a virtual console.

Notes:

The way coreutils knows who is logged in is by referencing a file, 
referenced as UTMP_FILE in the coreutils source code, which should keep 
track of user logins. My guess is that something is not updating it in 
this case.

My current system config is a bit messy, so I will work on making a 
minimalist config file that can replicate this bug.