Log Message:
Update elasticsearch to 2.4.1

=== Enhancements

Allocation::
- Change DiskThresholdDecider's behavior when factoring in leaving shards

Cluster::
- Add clusterUUID to RestMainAction output

=== Bug fixes

Core::
- Guard against negative result from FileStore.getUsableSpace when pick...

Highlighting::
- skip GeoPointMultiTermQuery when highlighting
- Fix highlighting of MultiTermQuery within a FunctionScoreQuery

Index APIs::
- Fix IndexNotFoundException in multi index search request.

Internal::
- Don't fail replica if FlushNotAllowedEngineException is thrown

Network::
- Don't send exception responses twice

Packaging::
- Fix Windows GC options

Query DSL::
- Fail parsing when match query contains an array of terms

REST::
- Correct the description for refresh

Reindex API::
- Make reindex tests a little less flaky

Scripting::
- Native scripts should be created once per index, not per segment.

Settings::
- Validate max thread/merge settings