storage-domain: use explicit initialization of struct OvirtXmlElement members
storage-domain: use explicit initialization of struct OvirtXmlElement members

Also, members have been reordered and the xml_node field has been
renamed to more proper xml_path.

Signed-off-by: Eduardo Lima (Etrunko) <025eb0974a9f48eaca88b86d8c2bcaf361e95a91@redhat.com>

etrunko/libgovirt,etrunko/libgovirt,GNOME/libgovirt