Add elasticsearch to the mediawiki node

elasticsearch is needed for the CirrusSearch MediaWiki extension,
which would be a much nicer search than the default database
search currently being done.

Change-Id: I2e014ff6713c9ed797bece482ea4460cbffb1300

modules/openstack_project/manifests/wiki.pp

@@ -56,4 +56,10 @@ class openstack_project::wiki (
     backup_user   => 'bup-wiki',
     backup_server => 'ci-backup-rs-ord.openstack.org',
   }
+
+  class { 'elasticsearch':
+    discover_nodes        => ['localhost'],
+    elasticsearch_version => '0.90.5',
+  }
+
 }