Bug#767357: elasticsearch: Move the jar to a libelasticsearch-java package

[Hilko Bengen]

control: tag -1 pending

* Emmanuel Bourg:

> The Maven artifact is bundled in the elasticsearch package, it would be
> preferable to package it separately in a libelasticsearch-java package
> such that elasticsearch plugins can be built without installing the server.

I have created a "todo" branch in the git repo and pushed the necessary
change there.

Cheers,
-Hilko