[BUGFIX] Fix bug with signalslotdispatcher in latest master

Change-Id: I06343c99d41253a56ea2f77fdc5d833da3ba5893
Reviewed-on: http://review.typo3.org/34481
Reviewed-by: Sebastian Fischer <typo3@evoweb.de>
Tested-by: Sebastian Fischer <typo3@evoweb.de>