Comment 22 for bug 684875

Scott Moser has explained to me why this is probably too invasive to fix in Maverick (hardcoded device names in /etc/fstab). I think I have an idea for how to work around this in Maverick's grub package by observing that an earlier comment in this bug indicates that the xen-blkfront /dev/sd* devices have a non-standard major number; I should be able to use that to detect a Xen block device.