title: Elasticsearch phrase suggester collate returns false even if query brings results back
body: <p>So I have following phrase suggester template:</p>
  
  <pre><code>PUT /_search/template/DidYouMean
  {
    "template": {
      "size": 0,
      "suggest": {
        "DidYouMean": {
          "text": "{{SearchPhrase}}",
          "phrase": {
            "field": "_all",
            "analyzer": "simple",
            "size": 50,
            "real_word_error_likelihood": 0.9,
            "max_errors": 0.5,
            "gram_size": 3,
            "direct_generator": [
              {
                "field": "_all",
                "suggest_mode": "always",
                "min_word_length": 3
              }
            ],
            "collate": {
              "prune": true,
              "query": {
                "match": {
                  "_all": {
                    "query": "{{suggestion}}"
                  }
                }
              }
            }
          }
        }
      }
    }
  }
  </code></pre>
  
  <p>And I run it using this query:</p>
  
  <pre><code>POST /my_index/_search/template
  {
    "template": {
      "id": "DidYouMean"
    },
    "params": {
      "SearchPhrase": "unileve"
    }
  }
  </code></pre>
  
  <p>And I'm expecting to get Unilever (a company) as a result with <code>"collate_match": true</code>, however, it's bringing back <code>false</code>. I'm getting this, even though I'm expecting Unilever to come with true:</p>
  
  <pre><code>{
     "took": 25,
     "timed_out": false,
     "_shards": {
        "total": 5,
        "successful": 5,
        "failed": 0
     },
     "hits": {
        "total": 220692,
        "max_score": 0,
        "hits": []
     },
     "suggest": {
        "DidYouMean": [
           {
              "text": "unileve",
              "offset": 0,
              "length": 7,
              "options": [
                 {
                    "text": "unilever",
                    "score": 0.016954133,
                    "collate_match": false
                 },
                 {
                    "text": "unilevers",
                    "score": 0.005391976,
                    "collate_match": false
                 },
                 {
                    "text": "unilet",
                    "score": 0.00062763924,
                    "collate_match": false
                 },
                 {
                    "text": "uniline",
                    "score": 0.00062518474,
                    "collate_match": false
                 },
                 {
                    "text": "unilerver",
                    "score": 0.00055350363,
                    "collate_match": false
                 },
                 {
                    "text": "uniliver",
                    "score": 0.00055350363,
                    "collate_match": false
                 },
                 {
                    "text": "unielever",
                    "score": 0.0005243993,
                    "collate_match": false
                 }
              ]
           }
        ]
     }
  }
  </code></pre>
  
  <p>Now when I run same query on its own, it brings result back.</p>
  
  <pre><code>POST /my_index/_search
  {
    "query": {
      "match": {
        "_all": {
          "query": "unilever"
        }
      }
    }
  }
  </code></pre>
  
  <p>It does bring results back.</p>
  
  <pre><code>{
     "took": 4,
     "timed_out": false,
     "_shards": {
        "total": 5,
        "successful": 5,
        "failed": 0
     },
     "hits": {
        "total": 4305,
        "max_score": 3.1709287,
        "hits": [
           {
              "_index": "my_index",
              "_type": "companies",
              "_id": "754743",
              "_score": 3.1709287,
              "_source": {
                 "CompanyName": "Unilever Iran Co"
              }
           },
           {
              "_index": "my_index",
              "_type": "companies",
              "_id": "751585",
              "_score": 3.1709287,
              "_source": {
                 "CompanyName": "Unilever UK Ltd"
              }
           },
           {
              "_index": "my_index",
              "_type": "companies",
              "_id": "10363",
              "_score": 3.1709287,
              "_source": {
                 "CompanyName": "Unilever (Schweiz) AG"
              }
           },
           {
              "_index": "my_index",
              "_type": "companies",
              "_id": "647311",
              "_score": 3.1709287,
              "_source": {
                 "CompanyName": "Unilever Taiwan Ltd"
              }
           },
           {
              "_index": "my_index",
              "_type": "companies",
              "_id": "651158",
              "_score": 3.1709287,
              "_source": {
                 "CompanyName": "Unilever Gulf FZE"
              }
           },
           {
              "_index": "my_index",
              "_type": "companies",
              "_id": "654498",
              "_score": 3.1709287,
              "_source": {
                 "CompanyName": "Unilever China Ltd"
              }
           },
           {
              "_index": "my_index",
              "_type": "companies",
              "_id": "654664",
              "_score": 3.1709287,
              "_source": {
                 "CompanyName": "Unilever NV"
              }
           },
           {
              "_index": "my_index",
              "_type": "companies",
              "_id": "650307",
              "_score": 3.1709287,
              "_source": {
                 "CompanyName": "Unilever Canada Ltd"
              }
           },
           {
              "_index": "my_index",
              "_type": "companies",
              "_id": "710125",
              "_score": 3.1709287,
              "_source": {
                 "CompanyName": "Unilever Ltd"
              }
           },
           {
              "_index": "my_index",
              "_type": "companies",
              "_id": "722327",
              "_score": 3.1709287,
              "_source": {
                 "CompanyName": "Unilever Croatia"
              }
           }
        ]
     }
  }
  </code></pre>
  
  <p>Am I misuderstanding purpose of collate? Or I am simply doing something completely wrong. Please advice.</p>
  
  <p>Elasticsearch version: 1.7.3</p>