Add a capatilities xml file for s390x ,the capatility for IBM
Distro called KVMIBM,mainly focus on a KVM hypervious on S390x.
Also add a clitest by using virt-install.
For architecture "s390x",the disk and the network device are base
on "virtio" bus.The cdrom is based on "scsi".So set the default
cdrom bus as "scsi",the default bus as "virtio".Also the default
machine type is set to "s390-ccw-virtio" as it is the only supported
in "s390x".Also add a test cast of virt-install by cdrom in s390x.
(crobinso: Tweak test suite and minor formatting stuff)
Make it clear which ones are used for the caps unit tests, and which
are for cli/UI testing and can be updated at will. And drop a bunch
of outdated stuff.
