Fix memory leak in Connect.listAllDomains

free was missing for the pointer returned in domains by virConnectListAllDomains, so this has been fixed.

cf. https://libvirt.org/html/libvirt-libvirt-domain.html#virConnectListAllDomains



Signed-off-by: Mitsuru Kariya <mitsuru.kariya@nttdata.com>