os-release pretended we were Ubuntu for a while, to make packages
with different build steps for Debian and Ubuntu follow Ubuntu-like
code paths. This has now been fixed.

Reviewed-by: Simon McVittie <smcv@collabora.co.uk>
Signed-off-by: Héctor Orón Martínez <hector.oron@collabora.co.uk>
Differential Revision: https://phabricator.apertis.org/D4272