[cairo] Failure in big-trap test case

[Bryce Harrington]

The new 'big-trap' test case is failing:

   http://crucible.osdl.org/runs/cairo_report.html
   http://crucible.osdl.org/runs/3181/test_output/cairo-test/amd01/test

The error message is:

  Testing big-trap with image target (dev offset 0)
  Error: Cannot find reference image for ./big-trap-image-argb32-ref.png
  TEST: big-trap TARGET: image FORMAT: argb32 OFFSET: 0 RESULT: FAIL
  Testing big-trap with image target (dev offset 25)
  Error: Cannot find reference image for ./big-trap-image-argb32-ref.png
  TEST: big-trap TARGET: image FORMAT: argb32 OFFSET: 25 RESULT: FAIL
  ... etc ...

Bryce