virttest.aexpect: Fix old class Spawn definition.

The base class Spawn for ShellSession was defined in old way(class Spawn).
Then we can not use super() for inherited classes:
TypeError: super() argument 1 must be type, not classobj

Signed-off-by: Yu Mingfei <yumingfei@cn.fujitsu.com>
Merge pull request #624 from yumingfei/aexpect_spawn

Aexpect spawn's definition
Add attach_disk and dettach_disk in VM class.

Signed-off-by: yangdongsheng <yangds.fnst@cn.fujitsu.com>
Add test for svirt attach disk.

Signed-off-by: yangdongsheng <yangds.fnst@cn.fujitsu.com>
libvirt_svirt: Add test for some domain operations.

Test the operations with svirt.

Signed-off-by: yangdongsheng <yangds.fnst@cn.fujitsu.com>
Add add_security method in make_create_command method to add '--security'

Signed-off-by: yangdongsheng <yangds.fnst@cn.fujitsu.com>
Add test for svirt in virt-install.

Signed-off-by: yangdongsheng <yangds.fnst@cn.fujitsu.com>
Add filter in guest-os to allow svirt_install access it.

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