virttest: Add unittest for utils_conn module.

Signed-off-by: yangdongsheng <yangds.fnst@cn.fujitsu.com>
virttest: Add utils_conn module into virttest.

Signed-off-by: yangdongsheng <yangds.fnst@cn.fujitsu.com>
virt: add method 'get_uri_with_transport' into libvirt_vm.

Signed-off-by: yangdongsheng <yangds.fnst@cn.fujitsu.com>
libvirt: add test for virsh connect.

Signed-off-by: yangdongsheng <yangds.fnst@cn.fujitsu.com>
modify the all libvirt_vm.libvirtd to utils_libvirtd.

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