title: protractor fails to run with directConnect
body: <p>I'm trying to run protractor by connecting directly to Chrome, not running Selenium. As the docs say, this is possible by setting the <code>directConnect</code> to <code>true</code> in the config file.</p>
  
  <p>When I run protractor with <code>directConnect: true</code>, I get:</p>
  
  <blockquote>
    <p>Using ChromeDriver directly...<br>
    [launcher] Running 1 instances of
    WebDriver Error: spawn ENOENT
        at errnoException (child_process.js:1001:11)
        at Process.ChildProcess._handle.onexit (child_process.js:792:34) [launcher] Process exited with error code 1</p>
  </blockquote>
  
  <p>If I run protractor without <code>directConnect</code> and instead specify my selenium url, everything runs fine. </p>
  
  <p>I'm running Protractor version 1.6.1, Chrome version 41.0.2272.35 beta-m (64-bit), and Chromedriver version 2.13.0.</p>