fix missing .dup, and support falling back to short_message in remap_gelf()
fix missing .dup, and support falling back to short_message in remap_gelf()

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