virt: unattended_install + qemu_vm update for openSuse 12.3 support

The unattended_install was not properly renaming kernel/initrd files for libvirt because the driver_type parameter was still referring to the legacy <code>kvm</code> test-driver name.  I updated it and and <code>qemu_vm</code> to the new <code>qemu</code> which <code>libvirt_vm</code> used anyway.

I added a definition for OpenSuse 12.3 support and modernized the cdrom device name from <code>scd0</code> to <code>sr0</code>.  I tested the <code>unattended_install.cdrom.extra_cdrom_ks</code> on a F18 host with both <code>-t libvirt</code> and <code>-t qemu</code>.

I searched around a bit, but could use some help checking if any other <code>qemu</code> tests or code could be affected by my update to <code>vm.driver_type</code> change (from kvm to qemu).  

Thanks