title: Firebase Swift: queryEqualToValue by childKey is not working
body: <p>Has anyone have any luck using the function:</p>
  
  <pre><code>.queryEqualToValue(value: AnyObject?, childKey: String?)
  </code></pre>
  
  <p>Two things: </p>
  
  <p>1) The childKey does not seem to allow deep paths, just direct children</p>
  
  <p>2) I can't get it to work at all! Given my structure: </p>
  
  <pre><code>"post": {
    "groupName": "hello world"
  }
  </code></pre>
  
  <p>If I do a simple:</p>
  
  <pre><code>postRef.queryEqualToValue("hello world", childKey: "groupName").observeSingleEvent( ... )
  </code></pre>
  
  <p>It does not return any posts at all. Instead I have to do the roundabout way of: </p>
  
  <pre><code>postRef.queryOrderedByChild("groupName").queryEqualToValue("hello world").observeSingleEvent( ... )
  </code></pre>
  
  <p>to get it to work!</p>
  
  <p><strong>Am I using the above function incorrectly?</strong></p>