Add utils_selinux in virttest.

Signed-off-by: yangdongsheng <yangds.fnst@cn.fujitsu.com>
Add unittest for utils_selinux

Signed-off-by: yangdongsheng <yangds.fnst@cn.fujitsu.com>
Add svirt test module in libvirt.

Signed-off-by: yangdongsheng <yangds.fnst@cn.fujitsu.com>