Comment 1 for bug 868977

The issue is that in MergeList for indexes without a architecture (like the Translations index) for Arch the main architecture is returned. So when the translated descriptions are added they will only be added for the main arch instead of for all arches.

Attached is a small fix for this but it needs some work as it makes the diff (with proper indent) pretty big and this is also a
good opportunity to simply this loop.