Add tests for virt-clone command.

Signed-off-by: Dongsheng Yang <yangds.fnst@cn.fujitsu.com>
Add test for virt-what command.

Signed-off-by: Dongsheng Yang <yangds.fnst@cn.fujitsu.com>
Merge pull request #245 from yangdongsheng/virt_cmd_lxc

Add tests for virt-xxx command in libvirt.