Set fuelweb_admin net on eth0 interface

In some cases after node updates we get situation
that fuelweb_admin net stay with some other net on
specisic interface. To avoid this situation set fuelweb_admin
on eth0 during node updates

Closes-Bug: #1525945
Change-Id: Ie38ca1b43a4e06835693f28c339f1e40b1e7f260

fuelweb_test/models/fuel_web_client.py

@@ -1321,6 +1321,7 @@ class FuelWebClient(object):
         net_provider = self.client.get_cluster(cluster_id)['net_provider']
         if NEUTRON == net_provider:
             assigned_networks = {
+                iface_alias('eth0'): ['fuelweb_admin'],
                 iface_alias('eth1'): ['public'],
                 iface_alias('eth2'): ['management'],
                 iface_alias('eth3'): ['private'],