title: telegraf not able to parse kafka consumer input
body: <p>I have a docker compose file:</p>
  
  <pre><code>   influx:
      image: influxdb:latest
      container_name: influxdb
      ports:
      - "8083:8083"
      - "8086:8086"
      - "8090:8090"
    telegraf:
      image: telegraf:latest
      container_name: telegraf
      links:
      - influx
      volumes:
      - ./telegraf.conf:/etc/telegraf/telegraf.conf:ro
    grafana:
      image: grafana/grafana:latest
      container_name: grafana
      ports:
          - "3000:3000"
      links:
          - influx
  </code></pre>
  
  <p>And I have a telegraf conf file in which I am taking kafka topics as input source</p>
  
  <pre><code>[[inputs.kafka_consumer]]
    ## topic(s) to consume
    topics = ["telegraf"]
  
    ## an array of Zookeeper connection strings
    zookeeper_peers = ["zookeeper:2181"]
    ## Zookeeper Chroot
    zookeeper_chroot = ""
    ## the name of the consumer group
    consumer_group = "telegraf_metrics_consumers"
    ## Offset (must be either "oldest" or "newest")
    offset = "oldest"
  
    ## Data format to consume.
    ## Each data format has it's own unique set of configuration options, read
    ## more about them here:
    ## https://github.com/influxdata/telegraf/blob/master/docs/DATA_FORMATS_INPUT.md
    data_format = "influx"
  </code></pre>
  
  <p>When I run <code>docker-compose up</code> , telegraf container doesn't start. It gives the below error:</p>
  
  <pre><code>Error parsing /etc/telegraf/telegraf.conf, line 1722: field corresponding to 'zookeeper_peers' is not defined in kafka_consumer.Kafka
  </code></pre>
  
  <p>However, I have defined <code>zookeeper_peers</code> in telegraf config.</p>