Make documentation for config items consistent with the code.
Make documentation for config items consistent with the code.

tinglinux/logstash-kafka,Aloomaio/logstash-kafka,joekiller/logstash-kafka,joekiller/logstash-kafka,Aloomaio/logstash-kafka,opentable/logstash-kafka,tinglinux/logstash-kafka,opentable/logstash-kafka