Fix: slots should add a special list, not a string.

Signed-off-by: Yu Mingfei <yumingfei@cn.fujitsu.com>
Fix: find_module should be given a list include pathes.

Signed-off-by: Yu Mingfei <yumingfei@cn.fujitsu.com>
Add Serial class for libvirt_xml/devices/serial module.

Signed-off-by: Yu Mingfei <yumingfei@cn.fujitsu.com>
Change the implement of get_devices in vm_xml module.

Signed-off-by: Yu Mingfei <yumingfei@cn.fujitsu.com>
Merge pull request #6 from yumingfei/libvirt_xml_devices

Libvirt xml devices