Comment 4 for bug 1792077

Hm, but we only add 'unit' to the disk_mapping if image meta has scsi controller model 'virtio-scsi' and we only increment the 'unit' number if 'unit' is found in the disk_mapping. So it would seem like we're safely only setting and incrementing 'unit' if we have image meta. So I don't get how the duplicate address is happening.