[Tails-l10n] (review) Tails 1.7 release-notes

Hi,
I translated the release-notes for version 1.7, please note for
reviewing, that three files are included:

wiki/src/news/version_1.7.de.po
wiki/src/inc/release_notes/1.7.de.po
wiki/src/security/Numerous_security_holes_in_1.6.de.po

https://gitlab.com/spriver/tails.git
branch: de_tails_17
commit: a2cb488b Initial translation

Cheers!
spriver