[TASK] Remove error_reporting from thumbs.php

Change-Id: I0aab3f628325fb2db3276d5d6d9e878e6328be0f
Resolves: #27250
Releases: 6.3, 6.2
Reviewed-on: http://review.typo3.org/32785
Reviewed-by: Markus Klein <klein.t3@reelworx.at>
Tested-by: Markus Klein <klein.t3@reelworx.at>