Description of problem:

http://libguestfs.org/virt-sysprep.1.html#fs-uuids-

I disabled the fs-uuids plugin in virt-sysprep because it
most likely breaks the guest.

To fix this we have to identify all the places in the guest
which use the UUID and fix them up.  eg:

 - /etc/fstab
 - initramfs
 - Windows boot loader
 - grub
 - others?

Version-Release number of selected component (if applicable):

1.23.13

How reproducible:

100%

Steps to Reproduce:
1. virt-sysprep --enable fs-uuids -a disk.img
2. Try to boot disk.img afterwards.

Actual results:

Guest won't be able to find and mount its root filesystem.