change logstash UTC to local time

change UTC to getLocalTime

logstash 2.1.1

/opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-core-2.1.1-java/lib/logstash/string_interpolation.rb
change @formatter = org.joda.time.format.DateTimeFormat.forPattern(@format) .withZone(org.joda.time.DateTimeZone::UTC)
to @formatter = org.joda.time.format.DateTimeFormat.forPattern(@format) .withZone(org.joda.time.DateTimeZone.getDefault())

logstash 2.2.1

/opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-core-event-2.2.1-java/lib/logstash/string_interpolation.rb
change @formatter = org.joda.time.format.DateTimeFormat.forPattern(@format) .withZone(org.joda.time.DateTimeZone::UTC)
to @formatter = org.joda.time.format.DateTimeFormat.forPattern(@format) .withZone(org.joda.time.DateTimeZone.getDefault())
useful doc