title: "cannot get automation extension" error with chrome 54.0.2840.71
body: <p>protractor version : <code>1.5.0</code></p>
  
  <p>chrome version : <code>54.0.2840.71 m (64-bit)</code></p>
  
  <p>protractor failed to launch chrome with the following error:</p>
  
  <p><code>Using ChromeDriver directly...
  [launcher] Running 1 instances of WebDriver
  [launcher] Error: UnknownError: unknown error: cannot get automation extension
  </code></p>