contrail-api workers rabbit health check should be disabled

[Petr Jediný]

As contrail-api workers should be producers only, consumer health check interval should not be applied.

```
    parser.add_argument(
        "--rabbit_health_check_interval",
        help="Interval seconds between consumer heartbeats to rabbitmq")
```

This also silences log message:
`Error in rabbitmq heartbeat greenlet: Too many heartbeats missed`

[OpenContrail Admin (ci-admin-f)]

Review in progress for https://review.opencontrail.org/40834
Submitter: Petr Jediný (<email address hidden>)

[OpenContrail Admin (ci-admin-f)]

Reviewed: https://review.opencontrail.org/40834
Committed: http://github.com/Juniper/contrail-controller/commit/276d69a93288c167583596524cf8310c79f1bddf
Submitter: Zuul v3 CI (<email address hidden>)
Branch: master

commit 276d69a93288c167583596524cf8310c79f1bddf
Author: Petr Jediný <email address hidden>
Date: Mon Mar 19 19:55:16 2018 +0100

Do rabbit health check on worker 0 only

contrail-api workers > 0 are producers only, this patch disables
consumer health checks on workers with id > 0.

This silences log message:
Error in rabbitmq heartbeat greenlet: Too many heartbeats missed

Change-Id: I8d3a29b5c80c770c9b2bc924fd6d8d725fc9725b
Closes-Bug: #1756968