- Use DefaultDependencies=no in ifup@.service so the service can be started
as early as possible.
- Create the ifupdown runtime directory in ifup@.service as we can no longer
rely on the networking service to do that for us.
- Don't stop ifup@.service on shutdown but let the networking service take
care of stopping all hotplugged interfaces.
- Only start ifup@.service for interfaces configured as allow-hotplug.
This ensures that ifdown is run when the device is removed and the
service is stopped. Closes: #660861, #703033
We eventually should rework that and instead of calling systemctl in
net.agent, start the service directly from the udev rule via
ENV{SYSTEMD_WANTS}.
