[libvirt] how do I stop libvirt futzing with my network configuration?

[Nix]

On 30 Nov 2009, Daniel P. Berrange stated:
> What's confusing it here is that you've not connected a real physical
> network interface to the bridge - it is expecting to find a ethernet
> device enslaved, and instead finds 'dummy0'.

I'm not bothering with dummy0 anymore: my bridges are empty save for VM
network interfaces (connected to the real network via ordinary routing).
Let's see if this works with the virt-manager/libvirt fix Cole
mentioned...