Revert "Update HOSTNAME in grok-patterns"
Revert "Update HOSTNAME in grok-patterns"

This reverts commit a17f72150d347ce53521aa709f45fea818c3385f.
This change caused a syntax error in the HOSTNAME pattern I believe.

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