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.
(cherry picked from commit 8de1bec803)
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/.
(cherry picked from commit f79d62692e)
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
