Code review comment for ~canonical-bootstack/charm-openstack-service-checks:feature/contrail-service-checks

keystone.yaml will be removed per conversation, so use the already existing nagios.novarc config file. I've also suggested a minor change on the contrail_vip property, as I was recommended in the past by the OpenStack charmers.

We may want to validate that the contrail_vip is valid and make "check_contrail_alarms.py -H <vip>" work.