systemd ships nice.conf override for wrong service

[Nick Rosbrook]

[Impact]

Prior to Noble (since Bionic or so), we shipped systemd-journald.service with Nice=-1 due to bug 1696970. In Noble, we intended to do this with a drop-in config instead of an out-of-tree patch [1]. But, this drop-in was mistakenly shipped for systemd-logind.service, instead of systemd-journald.service. This means the mitigation for bug 1696970 is no longer in place on Noble, and users could potentially see regressions.

[Test]

Check that systemd-journald.service has Nice=-1 configured (and that systemd-logind.service does not):

$ systemctl show -p Nice systemd-journald.service
$ systemctl show -p Nice systemd-logind.service

[Where problems could occur]

Clearly, we should be careful that the drop-in is shipped for the correct service, otherwise we may apply the setting to the wrong unit.

[Other information]

I have not actually seen any regressions reported about this, but as we intended to keep the Nice=-1 setting for systemd-journald.service, we should restore it.

[1] https://git.launchpad.net/~ubuntu-core-dev/ubuntu/+source/systemd/commit/?h=ubuntu-noble&id=9605a17332ee8a8dc9b390bd24acf116184b69d2