Comment 2 for bug 1520288

Please, take a look at that issue. It stopped working after fuel-8.0-169-2015-11-16_13-42-00.iso
We got such error before - https://github.com/openstack/fuel-web/blob/master/nailgun/nailgun/api/v1/validators/network.py#L532

And now admin net can be successfully bonded in LACP