[PR Updated] virttest.libvirt_xml.vm_xml: Add option to get_disk_resource

New: Update the PR to suit the change of repo split.  (2014-01-28)
Only include one commit in this:

    virttest.libvirt_xml.vm_xml: Add option to get_disk_resource
    
    Add option to get_disk_resource to support extra option when
    dumpxml.

Old log:
Add virsh domblklist test

What's New:
2014-01-09:
As bug 1049529 fixed the --config flag with running domain for attach/detach-disk problem, update the domblklist to use --config rather than --live --config flag when domain is running and --inactive is specified for domblklist.