Bug#760649: systemd: caused by user's homedir not existing

[Ray Kohler]

Package: systemd
Version: 215-5+b1
Followup-For: Bug #760649

This appears to be caused by exiting a systemd user session when the
user's home directory doesn't exist. In this case, the user is "nobody",
and the homedir is "/nonexistent". When systemd starts
systemd-exit.service to run the kill command, it tries to "cd
/nonexistent" and gets this error. Since the session is dying at this
point anyway, it's more a nuisance than a real problem.

An easy way to trigger this bug is to install (and enable)
popularity-contest. That package su's to nobody in
/etc/cron.daily/popularity-contest . (Running the script by hand won't
trigger the bug, cron has to do it.)