fluentd elasticsearch plugin has dropped support for ruby versions below 2.3

[Dincer Celik]

fluentd elasticsearch plugin now requires at least ruby 2.3 which is not possible to run on ubuntu/debian for rocky. The last version of the elasticsearch plugin which can run with ruby below 2.3 is 4.0.0, so we need to pin to it.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/rocky
Review: https://review.opendev.org/706713

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/706713
Committed: https://git.openstack.org/cgit/openstack/kolla/commit/?id=21dabe0bef392a413b9b4ec03395ebcc66f63273
Submitter: Zuul
Branch: stable/rocky

commit 21dabe0bef392a413b9b4ec03395ebcc66f63273
Author: Dincer Celik <email address hidden>
Date: Sun Feb 9 17:39:05 2020 +0300

    Fixes fluentd for rocky

    Pin fluent-plugin-elasticsearch to 4.0.0

    fluent-plugin-elasticsearch now requires at least ruby 2.3 which is
    not possible to run on ubuntu/debian for rocky after
    https://review.opendev.org/#/c/704040/

    [1] https://rubygems.org/gems/fluent-plugin-elasticsearch/versions/4.0.0
    [2] https://rubygems.org/gems/fluent-plugin-elasticsearch/versions/4.0.1

    Closes-Bug: #1862522

    Change-Id: I94695b03791b1028d528052d772fc302ab8080ee

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/kolla 7.1.1 release.