Extra cdrom ks installation

In RHEL7.0,  floppy drive has removed from installation kernel and ramdisk, so install rhel7 guest from floppy test was block and  floopy does not support by qemu if machine type is 'q35' too, so we need to support extra  windows guest from extra_cdrom_ks test. this patch set do that we want to do.

Thanks,
Xu