[Tails-l10n] Error in hu.po

Hi!

While preparing Tails 4.19~beta1 I encountered a problem:

    git checkout testing && \
    ./import-translations  && \
    ./refresh-translations && \
    ./submodules/jenkins-tools/slaves/lint_po

which reports:

    po/hu.po:1874: a format specification for argument 'manual_upgrade_url' doesn't exist in 'msgstr'

It would be great if this is fixed before 4.19 final, latest

Cheers!