Update JRuby auto-installer in bin/logstash to use JRuby 1.7.5 (cherry picked from commit 733b2bb)
Update JRuby auto-installer in bin/logstash to use JRuby 1.7.5
(cherry picked from commit 733b2bb)

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