The main reason to introduce the "no-wait.d" dispatcher directory was
"10-ifcfg-rh-routes.sh", which (as a pre-up script) delays activation.
We even extracted the script to a separate package on RHEL to avoid
delays by default.

Invoke the script via no-wait.d.

Routing table entries for a device get flushed when the device is
deactivated, but rules table entries don't, so we have to flush them
by hand.

If a connection has an associated "rule-NAME" or "rule6-NAME" file,
don't try to read in the routes, since NetworkManager won't be able to
parse them correctly. Instead, log a warning that they will need to be
applied via a dispatcher script, and provide a script that would do
that in examples/dispatcher/.

Tighten up with suggestions from  Johannes Buchner and mention
his contribution.

Also fixes operation with current nmcli since it changed from
"802-3-ethernet" -> "ethernet" and thus the script was broken.

https://bugzilla.gnome.org/show_bug.cgi?id=513488