Comment 2 for bug 1307429

As far as I know, Ubuntu never supported the allow-hotplug syntax, we instead treat everything as hotplug so long as they are marked auto.

I believe we have this documented somewhere though I'm failing to find it at the moment...

Anyway, making allow-hotplug considered as equivalent to auto should be fine though it's not really urgent as I believe this just never worked (so can wait till next cycle probably).