Correctly set RUBYLIB for JRuby.
[rabbitmq] March Hare 2.1.0+

[Release notes](http://blog.rubyrabbitmq.info/blog/2014/01/16/march-hare-2-dot-1-0-is-released/): nothing that may affect Logstash, though.
kv=cleanup
Restore the fitler thread safety check that was mysteriously lost, I think, in the new pipeline rewrite for 1.2.0 (LOGSTASH-1828)

Also mark the metrics filter as not threadsafe.
Include filter-worker validation before saying the config is good.
Merge pull request #981 from jordansissel/abort-on-not-threadsafe-filters

Restore the fitler thread safety check that was mysteriously lost, I thi...
Merge pull request #979 from kurtado/doc/filter/kv

kv=cleanup (docs improvements)
Merge pull request #970 from michaelklishin/patch-1

[rabbitmq] March Hare 2.1.0+
Work around mutex lock in geoip ruby module. Doing it this way consumes slightly more memory but unblocks the threads when there is a high amount of concurrency against geoip lookups (eg, when you are processing web server logs).
Merge pull request #990 from avleen/geoip_mutex

Work around mutex lock in geoip ruby module. This measurably helps performance by avoiding locking when using multiple filter workers. Every copy of a geoip filter in each filter worker now gets a thread-local GeoIP handle.
Merge pull request #941 from buckett/jruby-dev

Correctly set RUBYLIB for JRuby.
Remove long-deprecated/unused 'debug' setting for all plugins that do
not use it.

Also deprecated the 'debug' setting for plugins that *do* use it with
encouragement to use the --debug flag.
input/collectd: Fix crash

  * The plugin would crash if an encrypted packet was received and no
    authfile was configured. This commit fixes this.
Merge pull request #996 from jordansissel/remove-unused-debug-setting

Remove long-deprecated/unused 'debug' setting for all plugins that do not use it
Merge pull request #994 from pieterlexis/fix_collectd_crash

input/collectd: Fix crash
Allow multiple GeoIP filters (fixes bug introduced in #990)

This fixes LOGSTASH-1842 by using a per-object thread-local key name.

Previously (via #990), all geoips would compete over the same
threadlocal key name :geoip. Now the threadlocal key is
'geoip-<the geoip filter object id>' which allows each instance of geoip
to use a unique key and not share with another filter instance.
Merge pull request #997 from jordansissel/fix-thread-local-geoip

Allow multiple GeoIP filters (fixes bug introduced in #990)
Move external gem requires to #register
Merge pull request #998 from jordansissel/fix-docs-building

Move external gem requires to #register
Ubuntu/Debian should depend on 'java-runtime-headless'

This fixes #893. The previous dependency "default-jre-headless" is just
a metapackage pointing at openjre6, but "java6-runtime-headless" is a
'Provides' entry that openjdk packages seem to provide for java versions
6 and 7. This should ensure we are correctly requesting *any* java 6+
implementation instead of requiring a specific java package.