title: Change LoopBack default error object
body: <p>In LoopBack, when a required parameter of an API is missed, it will return some errors like this:</p>
  
  <pre><code>{
      "error": {
          "statusCode": 400,
          "name": "Error",
          "message": "fields is a required argument"
      }
  }
  </code></pre>
  
  <p>But what I want is an error like this:</p>
  
  <pre><code>{
      "response status": 400,
      "response body": {
          "message": "fields is a required argument"
      }
  }
  </code></pre>
  
  <p>How should I change the default error structure in LoopBack?</p>