bug-fix for when id is not specified for elasticsearch. making it not required.  LOGSTASH-256
bug-fix for when id is not specified for elasticsearch. making it not required.  LOGSTASH-256

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