Give elasticsearch more heap memory.

* modules/logstash/files/elasticseach.default: Elasticsearch does not
handle running out of memory very gracefully. Recommended allocation is
half of the hosts memory. Give elasticsearch 4GB of the 8GB host.

* modules/logstash/manifests/elasticseach.pp: Copy new elasticsearch
defaults file into place on the host.

Change-Id: I9ed14148c901cd3fd4ec38333a722821adb77ff5
Reviewed-on: https://review.openstack.org/27870
Approved: Clark Boylan <clark.boylan@gmail.com>
Reviewed-by: Clark Boylan <clark.boylan@gmail.com>
Tested-by: Jenkins
Turn on log-pusher.py debug logging.

* modules/openstack_project/templates/logstash/indexer.conf.erb: Enable
log-pusher.py debug logging to help determine why logstash is restarting
the log-pusher and to see why the logs stop flowing at times.

Change-Id: I250a6400c2fd29201865e9f8c5761dc2f4fbf5c3
Reviewed-on: https://review.openstack.org/27871
Approved: Clark Boylan <clark.boylan@gmail.com>
Reviewed-by: Clark Boylan <clark.boylan@gmail.com>
Tested-by: Jenkins