net: getLinks: avoid redundant list creation

Returning an iterator is cheaper than creating a possibly-long
throwaway list.

Change-Id: I566b145d76dee6724a4d84c45d9cb2098fae9df7
Signed-off-by: Dan Kenigsberg <danken@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/32844
Reviewed-by: Antoni Segura Puimedon <asegurap@redhat.com>