title: Elasticsearch TTL not working
body: <p>I use elasticsearch for logs, I don't want to use daily index to delete them with a cron job but with the TTL. I 've actived and set TTL with the value: 30s. I have a succesfull answer when I send this operation and I can see the TTL value(in milliseconds) when I do the mapping request.
  All seems good but documents are not be deleted... </p>
  
  <p>_mapping :</p>
  
  <pre><code>{
      "logs" : {
          "webservers" : {
              "_ttl" : {
                  "default" : 30000
              },
              "properties" : {
                  @timestamp" : {         
                      "type" : "date",
                      "format" : "dateOptionalTime" 
                  }
              }
          }
      }
  }
  </code></pre>