Code review comment for ~danilogondolfo/network-manager/+git/network-manager:new_autopkgtests

Thank you! LGTM. I left one little (non-blocking) inline comment, which you could consider fixing.

This MP depends on some fixes in libnetplan, so we should hold it back until those fixed landed in Mantic. Once that's done (and the new autopkgtests PASS), we should rebase this MP against https://code.launchpad.net/~network-manager/network-manager/+git/ubuntu/+ref/ubuntu/master and get it landed via the offical NetworkManager package.