We started systemd-vconsole-setup in two ways: via a dbus call from localed to
do systemd-vconsole-setup.service/restart, and from udev, calling the binary
directly. This patch makes udev call
systemctl restart systemd-vconsole-setup.service
effectively implementing the same method as localed.
Ordering is implemented at the unit level, so we can use --no-block to not
block here.