Enable ARP responder for L2 population

Local ARP responder is needed to serve ARP broadcasts locally on compute node
by neutron OVS agent. This is a part of L2 population feature.

Closes-bug: #1483584
Change-Id: Ic1f1809fa93fa8fc715ff638a9e365b49a0e1af4

deployment/puppet/openstack/manifests/network/neutron_agents.pp

@@ -94,6 +94,7 @@ class openstack::network::neutron_agents (
       tunnel_types               => $tunnel_types,
       enable_distributed_routing => $agent_mode ? { 'legacy' => false, default => true},
       l2_population              => $l2_population,
+      arp_responder              => $l2_population,
       manage_service             => true,
       enabled                    => true,
     }

tests/noop/spec/hosts/openstack-network/openstack-network-compute_spec.rb

@@ -188,6 +188,9 @@ describe manifest do
         should contain_class('openstack::network').with(
                    'l2_population' => neutron_l2_pop
                )
+        should contain_class('neutron::agents::ml2::ovs').with(
+                   'arp_responder' => neutron_l2_pop,
+               )
       end
 
       enable = Noop.hiera_structure('neutron_config/L2/segmentation_type') == 'gre'

tests/noop/spec/hosts/openstack-network/openstack-network-controller_spec.rb

@@ -134,6 +134,9 @@ describe manifest do
            should contain_class('openstack::network').with(
              'l2_population' => l2_pop,
            )
+           should contain_class('neutron::agents::ml2::ovs').with(
+             'arp_responder' => l2_pop,
+           )
         end
       end