Comment 8 for bug 784937

I am currently discussing this upstream. My impression is that this may be an intended change to get a sane way of naming the xvd devices when the configuration may mix hd and sd naming. So there is a 4 device offset done in the enumeration of xvd devices for disks named sd? in the configuration. That means hda-hdd become xvda-xvdd and sda, sdb, ... become xvde, xvdf, ...

Before that hda could become xvda and sda as well. Not really sure how it would work when having both.