[Tails-l10n] (review)[de] Upgrade error pages

Hi,
another branch to review:

https://gitlab.com/spriver/tails.git
branch: de_upgrade_error
HEAD commit: 4cf2819 Minor rephrasing

Affected files:
wiki/src/doc/upgrade/error.de.po
wiki/src/doc/upgrade/error/check.de.po
wiki/src/doc/upgrade/error/download.de.po
wiki/src/doc/upgrade/error/install.de.po



Cheers!
spriver