trivial: motd: disable updating motd for now
trivial: motd: disable updating motd for now

It looks like a systemd bug is happening, but let it be diagnosed upstream
systemd first.

https://github.com/systemd/systemd/issues/13688

hughsie/fwupd,hughsie/fwupd,hughsie/fwupd,fwupd/fwupd,fwupd/fwupd,hughsie/fwupd,fwupd/fwupd,fwupd/fwupd