Due to a systemd issue[1], using link files to rename interfaces
doesn't work as expected. Link files will not rename an interface
if it was already renamed, and interfaces are renamed in initrd, so
set-name will often not work as expected when rebooting.
However, rules files will cause a renaming, even if the interface
has been renamed in initrd.
So, while we sort out whether the systemd-udev behaviour is broken
or not, we can simply generate udev rules files with appropriate
renaming info in /run/udev/rules.d/70-netplan-<interface>.rules
A file will be created for non-virtual interfaces with both a
set-name and a driver or a mac address in the match stanza.
(Renaming from name to name doesn't work.)
Be explicit about enabling accept-ra; especially for systemd which might not
necessarily wait until the v6 IP is set (an RA received) unless we explicitly
tell it to accept RAs.
Also set mii-monitor-interval for test_bond_resend_igmp to attempt to force
it to be less flaky.
