Comment 2 for bug 1522980

 For HA router ports, only flood flows are notified and no unicast address are notified.

When flood flows are notified, agents create tunnel ports to HA router agents
and add flood flows for that HA router agent(and with that network) in br-tun.
ARP reply entries for HA router ports are not added in br-tun as
unicast addresses are not notified.

1) All HA routers create tunnel ports(and flood flows) to all agents hosting the network.
All HA routers create tunnels among themselves if tunnel is not created between them through above step.
(This will happen if the agent hosting HA router will have no other port in the network.)

2) All agents will be notified about the HA router agent. Along with that,
these agents will get notification about other HA router agents,
if they(i.e HA router agent) are not already hosting any other port in that network.
The intention is, other agents having ports on same network, create tunnel ports to
all HA router agents(if no tunnel ports are already present)

Note: In DB "ml2_port_bindings", shows that HA router port is bound to only one agent.
We will use "ha_router_agent_port_bindings" and "routerports" tables to get all agents
hosting the HA router. Some of these HA router agents might already have tunnel flows
to other agents(as they may be hosting other ports on the network).
So we skip them and consider only HA router agents hosting only HA router port.