title: Replacing a dot in an field name
body: <p>Good morning,</p>
  
  <p>Working on upgrading to the lastest version of the ELK stack and running into an issue with the field mapping. I have something similar to the following in my raw data:</p>
  
  <pre><code>{
    "_index" : "logstash-2016.04.21",
    "level1" : {
      "level2" : {
        "1" : "somevalue",
        "1.1" : "somevalue1"
      }
    }
  }
  </code></pre>
  
  <p>And as we all know elasticsearch 2.X does not like dots (.) in field names, messes up the dot-notation. So as a total newbie to elasticsearch, I have not been able to find a way, or search the right terms, to find a way to fix this using mappings or analyzers or 'something i do not yet know about'. I am hoping the community here can help me find a way to fix this so I can re-index all of my current indexes as well as mapping it for future indexes.</p>
  
  <p>Currently on ES version 1.7, running on debian</p>
  
  <p>Thank you,
  Mike</p>