title: Axios request : promise error UnhandledPromiseRejectionWarning after catch anyway
body: <p><br><br>
  I'm trying to manage errors properly in my code but I'm getting a warning like what I'm not handling the rejected promise, see below :</p>
  
  <pre><code>UnhandledPromiseRejectionWarning: Error: Request failed with status code 401
  at createError (/Users/a/Documents/export/node_modules/axios/lib/core/createError.js:16:15)
  at settle (/Users/a/Documents/export/node_modules/axios/lib/core/settle.js:18:12)
  at IncomingMessage.handleStreamEnd (/Users/a/Documents/export/node_modules/axios/lib/adapters/http.js:201:11)
  at IncomingMessage.emit (events.js:187:15)
  at endReadableNT (_stream_readable.js:1092:12)
  at process._tickCallback (internal/process/next_tick.js:63:19)
  </code></pre>
  
  <p>Here is my code :</p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-js lang-js prettyprint-override"><code>const axios = require('axios');
  axios.get('API_REQUEST', {
      'auth': {
          'bearer': 'NOT_WORKING_TOKEN' // To force the API to return an error ;)
      }
  }).catch((error)=&gt;{
      throw error;
  })</code></pre>
  </div>
  </div>
  </p>
  
  <p>For now I just want my program to crash without the warning when the error is throwing.</p>