Description of problem:
if I wish to assign 30 disks to a virtual machine, virt-install starts naming them wrongly after vdz (see "target dev=XXX"):

    <disk type='file' device='disk'>
      <driver name='qemu' type='raw' cache='writethrough'/>
      <source file='/var/lib/libvirt/images/shared-0025.img'/>
      <target dev='vdz' bus='virtio'/>
      <shareable/>
      <serial>STS-SHARED-0025</serial>
    </disk>
    <disk type='file' device='disk'>
      <driver name='qemu' type='raw' cache='writethrough'/>
      <source file='/var/lib/libvirt/images/shared-0026.img'/>
      <target dev='vd{' bus='virtio'/>
      <shareable/>
      <serial>STS-SHARED-0026</serial>
    </disk>
then it fails with:
Fri, 17 Feb 2012 13:02:13 DEBUG    Removing /var/lib/libvirt/boot/virtinst-vmlinuz.ThGVwx
Fri, 17 Feb 2012 13:02:13 DEBUG    Removing /var/lib/libvirt/boot/virtinst-initrd.img.9D8QWL
Fri, 17 Feb 2012 13:02:13 ERROR    An error occurred, but the cause is unknown
Fri, 17 Feb 2012 13:02:13 DEBUG    Traceback (most recent call last):
  File "/usr/sbin/virt-install", line 629, in start_install
    noboot=options.noreboot)
  File "/usr/lib/python2.6/site-packages/virtinst/Guest.py", line 1223, in start_install
    noboot)
  File "/usr/lib/python2.6/site-packages/virtinst/Guest.py", line 1291, in _create_guest
    dom = self.conn.createLinux(start_xml or final_xml, 0)
  File "/usr/lib64/python2.6/site-packages/libvirt.py", line 2064, in createLinux
    if ret is None:raise libvirtError('virDomainCreateLinux() failed', conn=self)
libvirtError: An error occurred, but the cause is unknown
Fri, 17 Feb 2012 13:02:13 DEBUG    Domain installation does not appear to have been successful.


Version-Release number of selected component (if applicable):
python-virtinst-0.600.0-5.el6.noarch

How reproducible:
always

Steps to Reproduce:
1. virt-install with many --disk options (30+)
2.
3.
  
Actual results:
abort as described in description, wrong names for targets

Expected results:
vdy, vdz, vdaa, vdab, kind of what linux kernel would name them
no error on virt-install

Additional info: