Comment 15 for bug 1841660

Below patch submitted.
https://review.opendev.org/#/c/695342/

Below error could not be seen anymore.
2019-11-20 03:09:00.172 24 ERROR neutron.agent.linux.iptables_manager [-] Failure applying iptables rules: OSError: [Errno 30] Read-only file system: '/var/lib/neutron/tmp'
2019-11-20 03:09:30.147 24 ERROR neutron.agent.l3.agent raise l3_exc.IpTablesApplyException(msg)
2019-11-20 03:09:30.147 24 ERROR neutron.agent.l3.agent IpTablesApplyException: Failure applying iptables rules

I can see router update finished in my test log.
2019-11-21 02:17:56.351 18 INFO neutron.agent.l3.agent [-] Finished a router update for 59e7e8e4-46e3-4a69-911e-0f0032457c29, update_id 3df534be-dc07-4829-ab28-1eef65aabb56.