Increase the queue_size of pending request to 1000

With a size of 50 we see a lot of messages like:
EsRejectedExecutionException[rejected execution (queue capacity 50)

So we increase this size of the bulk thread pool.

Change-Id: I4511061dc4681838779a84e362ca2bb26a2f5f9e

deployment_scripts/puppet/manifests/elasticsearch.pp

@@ -45,9 +45,10 @@ if $elasticsearch_kibana['node_name'] == hiera('user_node_name') {
   # Start an instance of elasticsearch
   elasticsearch::instance { $es_instance:
     config => {
-      'bootstrap.mlockall'     => true,
-      'http.cors.allow-origin' => '/.*/',
-      'http.cors.enabled'      => true
+      'threadpool.bulk.queue_size' => '1000',
+      'bootstrap.mlockall'         => true,
+      'http.cors.allow-origin'     => '/.*/',
+      'http.cors.enabled'          => true
     },
   }