Add plan to fix #696093 soon.
Categorize adequate results.

* piuparts.py: categorize adequate results using inadequate_tags, boring_tags,
  ignored_tags and unknown. Show adequate exit code if non-zero.
* Add known_problems/*inadequate*.conf for all adequate tags we care
  about.

Signed-off-by: Holger Levsen <holger@layer-acht.org>