Comment 4 for bug 1662533

There is param "intarface" inside of network generation procedure:

https://github.com/openstack/fuel-qa/blob/stable/newton/fuelweb_test/tests/test_net_templates_base.py#L68

But it unsupported by fuel:
https://github.com/openstack/fuel-web/blob/stable/newton/nailgun/nailgun/extensions/network_manager/validators/json_schema/networks.py

That is why we got 400.
But the same validator used (may be) for Mitaka, and test passed...

So we should refactor network cases to exclude "interface" option for definition and for checking.