l10n: de.po: translate 2 messages

Translate 2 messages came from git.pot update in e447091
(l10n: git.pot: v2.6.0 round 2 (3 improvements)).

Signed-off-by: Ralf Thielow <[email protected]>
Acked-by: Phillip Sz <[email protected]>

Author: ralfth