Check compatible librdkafka at runtime

[kevinburke]

The consumer_example.go has this example for a Consumer:

	c, err := kafka.NewConsumer(&kafka.ConfigMap{
		"bootstrap.servers":    broker,
		"group.id":             group,
		"session.timeout.ms":   6000,
		"default.topic.config": kafka.ConfigMap{"auto.offset.reset": "earliest"}}

I had to change "earliest" to kafka.OffsetBeginning to get it to work. Currently the Kafka consumer is failing on No such configuration property: "session.timeout.ms". I'm not sure what's going on there, I'm currently trying to debug it.

[kevinburke]

The odd thing is these work locally (on Mac) but not in my CI environment (ubuntu). I installed librdkafka by running add-apt-repository "deb [arch=amd64] http://packages.confluent.io/deb/3.3 stable main" && apt-get update && apt-get install librdkafka1.

[kevinburke]

Ah, turns out I was using librdkafka 0.8.4 or so on that machine..

[edenhill]

So old!
We'll add a runtime check to verify the librdkafka version.