The tails-upgrade-frontend program now runs as this user, and it needs to reach
the Internet to get an upgrade-description file.

This reverts commits 945796fe
and 6bebc91c.

The APT pinning for linux*3.10* is actually useless, as these packages are not
in Debian testing anymore and will be covered by the general pinning rules that
apply to our own APT repository. Let's keep these lines around so that we don't
forget to adapt them once we move forward to a newer kernel again.

Else, many noisy and useless changes appear in PO files. If one commits right
after this stage without running refresh-translations first, despite what the
release process documentation says, this would make the Git history hard
to understand.