Elasticsearch 5.6.15

Description

This patch updates Opencast's Elasticsearch compatibility and the
internal Elasticsearch node to version 5.6.15, finally btinging us to a
recent (Feb 19, 2019), still supported version.

Steps to reproduce

None

Status

Assignee

Lars Kiesow

Reporter

Lars Kiesow

Criticality

None

Tags (folksonomy)

None

Components

Affects versions

Priority

Major
Configure