[libvirt] RFC: make <mac> element required?

Hi, I am about to fix https://bugzilla.redhat.com/show_bug.cgi?id=616721 It seems to me that problem is libvirt inserts a new element <mac address='...'> during parsing interface XML with random mac address which result in error described in BZ. I am not sure wheter to fix it just in virsh or in virDomainDetachDevice() as well. If in virsh, then other application may fail without knowing why. But isn't the second option too aggressive? Michal Privoznik