Automatic reconnection issue

Description
===========
I have a consumer attached to a single node kafka broker. Due to a network hiccup the connection was lost and the consumer considered the node down. However when the broker was already available the client hasn't reconnected. My understanding was that this should have happened automatically.

```
ott 09 20:42:51 redacted.org kafka2sentry[12302]: %3|1539117771.968|FAIL|rdkafka#consumer-1| [thrd:ssl://redacted-ip:9093/bootstrap]: ssl://redacted-ip:9093/1: 1 request(s) timed out: disconnect (average rtt 13
ott 09 20:42:51 redacted.org kafka2sentry[12302]: %3|1539117771.968|ERROR|rdkafka#consumer-1| [thrd:ssl://redacted-ip:9093/bootstrap]: ssl://redacted-ip:9093/1: 1 request(s) timed out: disconnect (average rtt 1
ott 09 20:42:51 redacted.org kafka2sentry[12302]: %3|1539117771.968|ERROR|rdkafka#consumer-1| [thrd:ssl://redacted-ip:9093/bootstrap]: 1/1 brokers are down
ott 09 20:43:39 redacted.org kafka2sentry[12302]: %3|1539117819.054|FAIL|rdkafka#consumer-1| [thrd:ssl://redacted-ip:9093/bootstrap]: ssl://redacted-ip:9093/1: 1 request(s) timed out: disconnect (average rtt 13
ott 09 20:43:39 redacted.org kafka2sentry[12302]: %3|1539117819.054|ERROR|rdkafka#consumer-1| [thrd:ssl://redacted-ip:9093/bootstrap]: ssl://redacted-ip:9093/1: 1 request(s) timed out: disconnect (average rtt 1
ott 09 20:43:39 redacted.org kafka2sentry[12302]: %3|1539117819.054|ERROR|rdkafka#consumer-1| [thrd:ssl://redacted-ip:9093/bootstrap]: 1/1 brokers are down
ott 09 20:44:52 redacted.org kafka2sentry[12302]: %3|1539117892.010|FAIL|rdkafka#consumer-1| [thrd:ssl://redacted-ip:9093/bootstrap]: ssl://redacted-ip:9093/1: 1 request(s) timed out: disconnect (average rtt 13
ott 09 20:44:52 redacted.org kafka2sentry[12302]: %3|1539117892.010|ERROR|rdkafka#consumer-1| [thrd:ssl://redacted-ip:9093/bootstrap]: ssl://redacted-ip:9093/1: 1 request(s) timed out: disconnect (average rtt 1
ott 09 20:44:52 redacted.org kafka2sentry[12302]: %3|1539117892.010|ERROR|rdkafka#consumer-1| [thrd:ssl://redacted-ip:9093/bootstrap]: 1/1 brokers are down
ott 09 20:45:48 redacted.org kafka2sentry[12302]: %3|1539117948.112|FAIL|rdkafka#consumer-1| [thrd:ssl://redacted-ip:9093/bootstrap]: ssl://redacted-ip:9093/1: 1 request(s) timed out: disconnect (average rtt 13
ott 09 20:45:48 redacted.org kafka2sentry[12302]: %3|1539117948.112|ERROR|rdkafka#consumer-1| [thrd:ssl://redacted-ip:9093/bootstrap]: ssl://redacted-ip:9093/1: 1 request(s) timed out: disconnect (average rtt 1
ott 09 20:45:48 redacted.org kafka2sentry[12302]: %3|1539117948.112|ERROR|rdkafka#consumer-1| [thrd:ssl://redacted-ip:9093/bootstrap]: 1/1 brokers are down
ott 09 20:46:39 redacted.org kafka2sentry[12302]: %3|1539117999.746|FAIL|rdkafka#consumer-1| [thrd:ssl://redacted-ip:9093/bootstrap]: ssl://redacted-ip:9093/1: 1 request(s) timed out: disconnect (average rtt 13
ott 09 20:46:39 redacted.org kafka2sentry[12302]: %3|1539117999.746|ERROR|rdkafka#consumer-1| [thrd:ssl://redacted-ip:9093/bootstrap]: ssl://redacted-ip:9093/1: 1 request(s) timed out: disconnect (average rtt 1
ott 09 20:46:39 redacted.org kafka2sentry[12302]: %3|1539117999.746|ERROR|rdkafka#consumer-1| [thrd:ssl://redacted-ip:9093/bootstrap]: 1/1 brokers are down
ott 09 20:47:35 redacted.org kafka2sentry[12302]: %3|1539118055.242|FAIL|rdkafka#consumer-1| [thrd:ssl://redacted-ip:9093/bootstrap]: ssl://redacted-ip:9093/1: 1 request(s) timed out: disconnect (average rtt 13
ott 09 20:47:35 redacted.org kafka2sentry[12302]: %3|1539118055.242|ERROR|rdkafka#consumer-1| [thrd:ssl://redacted-ip:9093/bootstrap]: ssl://redacted-ip:9093/1: 1 request(s) timed out: disconnect (average rtt 1
ott 09 20:47:35 redacted.org kafka2sentry[12302]: %3|1539118055.242|ERROR|rdkafka#consumer-1| [thrd:ssl://redacted-ip:9093/bootstrap]: 1/1 brokers are down
ott 10 13:15:07 redacted.org systemd[1]: Stopping Kafka to Sentry consumer...
ott 10 13:15:07 redacted.org systemd[1]: Started Kafka to Sentry consumer.
ott 10 13:15:07 redacted.org systemd[1]: Starting Kafka to Sentry consumer...
```

After restarting service the consumer happily reconnected.

How to reproduce
================

Checklist
=========
Please provide the following information:

- [x] confluent-kafka-python and librdkafka version (`confluent_kafka.version()` and `confluent_kafka.libversion()`): `('0.11.4', 721920)`, `('0.11.4', 722175)`
- [x] Apache Kafka broker version: confluent-kafka-2.11-1.0.1-1.noarch
- [x] Client configuration: ```{
"default.topic.config": {"auto.offset.reset": "largest"},
"ssl.ca.location": "/var/ssl/private/ca.crt",
"security.protocol": "ssl",
"bootstrap.servers": "...:9093",
"group.id": "sentry-importer",
}```
- [x] Operating system: CentOS Linux release 7.5.1804 (Core)
- [x] Provide client logs (with `'debug': '..'` as necessary)
- [ ] Provide broker log excerpts
- [ ] Critical issue