virt-libvirt: add configuration for virsh vcpuinfo

Signed-off-by: Li Yang <liyang.fnst@cn.fujitsu.com>
virt-libvirt: modify vcpuinfo() in libvirt_vm.py

Signed-off-by: Li Yang <liyang.fnst@cn.fujitsu.com>
virt-libvirt: modify vcpuinfo() in virsh.py

Signed-off-by: Li Yang <liyang.fnst@cn.fujitsu.com>
virt-libvirt: add test for virsh vcpuinfo

Signed-off-by: Li Yang <liyang.fnst@cn.fujitsu.com>