title: Can't open Storyboard with Xcode 6
body: <p>I have a project with 2 storyboards built in Xcode 5.1.
  When I open either of those in Xcode 6 I get this error. They never opened in any beta so I don't think it's a bug of Xcode. 
  Last tried in Xcode 6 GM.</p>
  
  <blockquote>
    <p>The document "Main_iPhone.storyboard" could not be opened. The operation couldn’t be completed. (com.apple.InterfaceBuilder error -1.)</p>
  </blockquote>
  
  <p>Log says this:</p>
  
  <pre><code>ibtoold[1880:1335652] Exception raised while unarchiving document objects - -[NSTaggedPointerString getCharacters:range:]: Range {0, 10} out of bounds; string length 9
      Recovery Suggestion: Check the console log for additional information.
  </code></pre>