A bug occured iOS 8.x.
That is display only black screen.
If OnGUI's drawing are successful.
Button, Label are drawed on screen.
But vuforia's camera drawing are not appeared.
## How To Reproduction
1. Boot your app with vuforia.
2. Click Home button, and app go to background.
3. Re-boot your app by icon.
4. iteration 2 and 3.
5. A black screen ( vuforia draw hardware camera's movie to plane poligon in unity scene space. ) drawn.
Please let me know how to fix this bug ! Help!