Ensure only one ES pod per PV

bug 1460564. Fixes [BZ #1460564](https://bugzilla.redhat.com/show_bug.cgi?id=1460564).

Unfortunately, the defaults for Elasticsearch prior to v5 allow more
than one "node" to access the same configured storage volume(s).

This change forces this value to 1 to ensure we don't have an ES pod
starting up accessing a volume while another ES pod is shutting down
when reploying. This can lead to "1" directories being created in
`/elasticsearch/persistent/${CLUSTER_NAME}/data/${CLUSTER_NAME}/nodes/`.
By default ES uses a "0" directory there when only one node is accessing
it.

roles/openshift_logging_elasticsearch/templates/elasticsearch.yml.j2

@@ -16,6 +16,7 @@ index:
 node:
   master: ${IS_MASTER}
   data: ${HAS_DATA}
+  max_local_storage_nodes: 1
 
 network:
   host: 0.0.0.0