[TASK] Remove $user->prepareDateOfBirth() from controllers

Change-Id: I5cb8e20069e4a5968c05ee8fcb9658285c89db78
Reviewed-on: http://review.typo3.org/33014
Reviewed-by: Sebastian Fischer <typo3@evoweb.de>
Tested-by: Sebastian Fischer <typo3@evoweb.de>