d/control: Update libautodie-perl recommendation

Signed-off-by: Niels Thykier <niels@thykier.net>
d/rules: Gracefully handle the absence of translations

Signed-off-by: Niels Thykier <niels@thykier.net>
po4a: Update pot file and discard da.po

The da.po was only used for the PoC and does not actually contain any
useful translations.

Signed-off-by: Niels Thykier <niels@thykier.net>
Release Lintian/2.5.26 into unstable

Signed-off-by: Niels Thykier <niels@thykier.net>