title: Elasticsearch not returning results for aggregate query but returns results for other queries
body: <p>hi I'm new to elastic search and when i try a aggregate query it is not returning any results.</p>
  
  <pre><code>http://localhost:9200/contract/_search?search_type=count
      {
        "aggregations": {
          "status_cons": {
            "terms": {
              "field": "data.policyStatus",
              "size": 0
            }
          }
        }
      }
  </code></pre>
  
  <p>Note: this is just one of the queries that i had tried ,I have give size as 0 with the query and remove the search type ,added a query term with match_all etc</p>
  
  <p>found out this is a bug in the head plugin. GET method doesn't work using the head plugin.</p>
  
  <p>Related dicussion :<a href="https://stackoverflow.com/questions/12195017/different-result-when-using-get-post-in-elastic-search">Different result when using GET/POST in elastic search</a></p>
  
  <p><a href="https://i.stack.imgur.com/71d71.png" rel="nofollow noreferrer">no results for aggregation</a></p>