This fixed the following dependency loop that could occur when the
system was booting up:
1. NetworkManager configures a network interface and fires off the clatd
dispatcher script.
2. The dispatcher scripts tries to restart `clatd.service`.
3. However, `clatd.service` cannot be (re)started at this point because
its dependency `network-online.target` has not yet been reached.
4. Therefore, the `systemctl restart clatd.service` command in the
dispatcher script blocks, waiting for `network-online.target` to be
reached.
5. But that won't happen until the dispatcher scripts finishes...
Adding `--no-block` allows the dispatcher script to finish immediately
without waiting for the restart to complete (instead, systemd will do it
in the background once `network-online.target` has been reached).
Furthermore, since `clatd.service` may end up being restarted several
times during a boot process (especially on a system with many network
interfaces handled by NetworkManager), it is also at risk of
inadvertently triggering the restart rate-limiting feature in systemd,
so disable that while we're at it.
Closes#22. Thanks to @patrakov for the report!
