rpc_workers and rpc_state_report_workers are set to 1 by default in
Neutron:
https://github.com/openstack/neutron/blob/master/neutron/conf/service.py#L30
By design neutron-server is a central RPC service for all agents (L2
agents, L3 agents, Metadata agents, LB agents, VPN agents, ...).
For a production ready cloud, these variables must be set to a greater
value than 1.
Change-Id: Ib39be32748c3ee8077941fd1659db12c9d80055c
Closes-Bug: #1671734