title: Mongoose returns undefined for an existing field
body: <p>After a mongoose request I have my document <code>doc</code> which is the result of the query</p>
  
  <p>Here is the schema used</p>
  
  <pre><code>var searchSchema = new mongoose.Schema({
      original : String,
      images : [String],
      image: String
  });
  </code></pre>
  
  <p>The model :</p>
  
  <pre><code>var searchModel = mongoose.model('Search', searchSchema);
  </code></pre>
  
  <p>Code used:</p>
  
  <pre><code>searchModel.findOne({original : input}, function (err, doc) {
      if (err) {
          console.log(err);
      }
      if (typeof doc !== "undefined") {
          console.log(doc);
                      console.log(doc.image);
      }
  });
  </code></pre>
  
  <p>The first <code>console.log</code>:</p>
  
  <pre><code>{ 
      _id: 531401bf714420359fd929c9,
      image: 'http://url.com/image.jpg',
      original: 'lorem ipsum dolor sit amet' 
  }
  </code></pre>
  
  <p>The second returns <code>undefined</code>, but the previous one does show an existing <code>image</code> property, which means that it exists.</p>
  
  <p>My schema doesn't have anything special so I don't understand what may be happening here..</p>