title: Elasticsearch regexp with space not working
body: <p>Let's assume I have books with titles indexed with <strong>ElasticSearch</strong> as following:</p>
  
  <pre><code>curl -XPUT "http://localhost:9200/_river/books/_meta" -d'
  {
  "type": "jdbc",
  "jdbc": {
  "driver": "org.postgresql.Driver",
  "url": "jdbc:postgresql://localhost:5432/...",
  "user": "...",
  "password": "...",
  "index": "books",
  "type": "books",
  "sql": "SELECT * FROM books"}
  </code></pre>
  
  <p>}'</p>
  
  <p>For instance, I have a book called <code>"Afoo barb"</code>.</p>
  
  <p>The following code (searching for <code>'.*foo.*'</code>) returns well the book:</p>
  
  <pre><code>client.search({
    index: 'books',
    'from': 0,
    'size': 10,
    'body' : {
      'query': {
        'filtered': {
           'filter': {
             'bool': {
                'must': {
                  'regexp': { title: '.*foo.*' }
                 }
              }
            }
          }
       }
    }
  });
  </code></pre>
  
  <p>But the following code (searching for <code>'.*foo bar.*'</code>) does not:</p>
  
  <pre><code>client.search({
    index: 'books',
    'from': 0,
    'size': 10,
    'body' : {
      'query': {
        'filtered': {
           'filter': {
             'bool': {
                'must': {
                  'regexp': { title: '.*foo bar.*' }
                 }
              }
            }
          }
       }
    }
  });
  </code></pre>
  
  <p>I tried to replace the space by <code>'\s'</code> or <code>'.*'</code> but it does not work either.</p>
  
  <p>I think the title is separated in terms (<code>['Afoo', 'barb']</code>) so it can't find <code>'.*foo bar.*'</code>. </p>
  
  <p>How can I ask Elasticsearch to search the regexp in the complete title ?</p>