Updated German translation
Updated German translation

Translation message_batch_confirmation did not match the english equivalent. Furthermore the old translation caused a Exception:

An exception has been thrown during the rendering of a template ("Unable to choose a translation.") in SonataAdminBundle::standard_layout.html.twig at line 19.
davidromani/SonataAdminBundle,davidromani/SonataAdminBundle,davidromani/SonataAdminBundle