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

[Nix]

On 26 Nov 2009, Daniel P. Berrange verbalised:

> If you don't want libvirt to create the bridge + setup IPtables rules
> then don't use the  net-XXX  commands / XML. That functionality is 
> not there for pointing libvirt to existing bridge devices.

Ah. All comes clear.

> If you already have a bridge configured, then just point the guest 
> directly at that bridge by name.

That seems to work: I thought it didn't, but that was my DHCP server
deciding to go catatonic on me.

The only remaining obvious problem is virt-manager-related, I think:
this log spam:

Nov 27 00:04:38 spindle err: 00:04:38.977: error : virLibConnError:383 : this function is not supported by the hypervisor: virConnectNumOfInterfaces
Nov 27 00:04:38 spindle err: 00:04:38.977: error : virLibConnError:383 : this function is not supported by the hypervisor: virConnectNumOfDefinedInterfaces

Emitting this *once a second* seems a bit... extreme. Can't it try once
and give up?