logging: enable HTTP CORS for fluentd ES instance

Elasticsearch package has been upgrade to 1.4.x in J.1.1.0 and J.1.2.0
(1.0.3 in J.1.0.0) but kibana web interface is not compatible with
elasticsearch 1.4.x or higher if you don't change the configuration on
the service.

Change-Id: I19c1a0b08aa63ca0fad6b1a2c390e13775efa443
Closes-bug: #1451828

manifests/logging/server.pp

@@ -40,7 +40,12 @@ class cloud::logging::server(
   include ::kibana3
   include cloud::database::nosql::elasticsearch
   include cloud::logging::agent
-  elasticsearch::instance {'fluentd' : }
+
+  # Elasticsearch 1.4 ships with a security setting that prevents Kibana from connecting.
+  # We need to allow http cors in fluentd instance.
+  elasticsearch::instance {'fluentd' :
+    config => { 'http' => { 'cors.enabled' => true } }
+  }
 
   @@haproxy::balancermember{"${::fqdn}-kibana":
     listening_service => 'kibana',

spec/classes/cloud_logging_server_spec.rb

@@ -39,7 +39,9 @@ describe 'cloud::logging::server' do
     end
 
     it 'configure an elasticsearch instance' do
-      is_expected.to contain_elasticsearch__instance('fluentd')
+      is_expected.to contain_elasticsearch__instance('fluentd').with(
+        :config => { 'http' => { 'cors.enabled' => true } }
+      )
     end
 
     context 'with default firewall enabled' do