[BUGFIX] Improve return of default email address for reporting tool

Change-Id: I89600c7f29aa02276066eecd160580681ade7ea4
Reviewed-on: http://review.typo3.org/32578
Reviewed-by: Fabien Udriot <fabien.udriot@ecodev.ch>
Tested-by: Fabien Udriot <fabien.udriot@ecodev.ch>