Upgrade Elasticsearch to version 5.2.2.

Upgrade Elasticsearch to version 5.2.1.

Upgraded Elasticsearch to version 5.2.0.

Use DISCOVERY_SERVICE env var (pires#29)

Upgraded Elasticsearch to version 5.1.2.

Removed bogus instruction in Dockerfile.

Upgraded Elasticsearch to version 5.1.1.

Fixes pires#23

Print plug-in install.

Upgraded Elasticsearch to version 5.0.1.

Upgraded Elasticsearch to version 5.0.0.