#965 lxsession does not update utmp

[Bruno Haible]

The /var/run/utmp file is meant to contain information about which user is logged in. This works fine for all session managers I've tested (gdm-wayland-session, startplasma-wayland, gnome-session-binary, cinnamon-session, mate-session, xfce4-session, lxqt-session, sway), but not for lxsession.

How to reproduce:

1. Download Fedora Rawhide LXDE. It contains lxsession 0.5.5.
2. Install it.
3. Reboot and log in.
4. Open a terminal.
5. Run who. It displays nothing.
6. Run who -a. It displays only two lines, one for "system boot" and one for "run-level 5".

Note that the lxdm-session process (parent of lxsession) has provided some details to systemd. So, systemd has informations about the session. But that's only one place where programs look for information about sessions. /var/run/utmp is the other one.