libvirt-test/pci_passthrough: Add a case in pcipassthrough to test SRIOV.

Signed-off-by: Dongsheng Yang <yangds.fnst@cn.fujitsu.com>
Merge pull request #53 from yangdongsheng/pci_passthrough

libvirt-test/sr-iov: Add a case in pcipassthrough to test SRIOV...