title: Elasticsearch can't update non dynamic settings
body: <p>I am trying to create a test analyzer to experiment on analysis on Elastic Search. I have an index created called "mytest" which is available and searchable, but when I try to create a custom analyzer I get below error </p>
  
  <pre><code>{
  "error": "ElasticsearchIllegalArgumentException[Can't update non dynamic settings[[index.analysis.analyzer.content.type, index.analysis.analyzer.content.tokenizer]] for open indices [[mytest]]]",
  "status": 400
  }
  </code></pre>
  
  <p>Now I am not sure on restrictions on updating settings but I could not find anything in documentation. I can create the analyze when creating the index, but update does not work.</p>
  
  <p>Using the source below to create analyzer</p>
  
  <pre><code>PUT mytest/_settings
  {
    "analysis" : {
      "analyzer":{
        "content":{
          "type":"custom",
          "tokenizer":"whitespace"
        }
      }
    }
  }
  </code></pre>
  
  <p>Any ideas ?</p>