[BUGFIX] Removed undefined variable in createExceptionHandler

Remove the undefined $exception variable in
ContentObjectRenderer::createExceptionHandler

Resolves: #63811
Releases: master
Change-Id: I1517f74f381534fdc264f39c8e4d425c3711e635
Reviewed-on: http://review.typo3.org/35348
Reviewed-by: Alexander Opitz <opitz.alexander@googlemail.com>
Tested-by: Alexander Opitz <opitz.alexander@googlemail.com>
Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Tested-by: Wouter Wolters <typo3@wouterwolters.nl>