NetworkManager 1.40 compatibility

[Lukas Märdian]

NetworkManager 1.40+ is adding empty [ethernet] sections by default into the keyfile settings of certain connection profiles, especially bridges.

This makes the test-suite fail when using the libnetplan backend integration, due to libnetplan assuming an ethernet connection in this context and adding a wakeonlan=True YAML setting, which is invalid for bridges (non-ethernet devices).

E.g. have a look at this test case:

[connection]
id=Test Write Bridge Main
uuid={}
type=bridge
interface-name=br0

[ethernet]

[bridge]

[ipv4]
address1=1.2.3.4/24,1.1.1.1
method=manual

[ipv6]
addr-gen-mode=default
method=auto

[proxy]

[Lukas Märdian (slyon)]

https://github.com/canonical/netplan/pull/300

[Lukas Märdian (slyon)]

Released as of v0.106