title: Selenium throwing 'no display specified' error when one exists
body: <p>I have a script that starts a Selenium server (if one is not already running) and then runs some acceptance tests in Codeception (with Firefox version 27, which is compatible with our Selenium 2.42.2). If I go onto the server (using VNC), the script runs and executes properly, however I'm using eclipse with RTC plugin, and it's set up so that you can make a build request, which will run that script on the server.</p>
  
  <p>For some reason it always fails with this error (or some variant of it):</p>
  
  <pre><code>15:42:26.125 WARN - Exception: Unable to connect to host 127.0.0.1 on port 7055 after 45000 ms. Firefox console output:
  Error: no display specified
  Error: no display specified
  </code></pre>
  
  <p>On the server, even if I manually do export DISPLAY, it still fails from RTC. As far as I can tell, there's nothing special in the build rules that would cause this. It it just because VNC happens to be a GUI, and it can't find a display from just a terminal?</p>