Do not add deleted items to query feeds (#456)
Do not add deleted items to query feeds (#456)

This change won't affect non-query feeds because `update_items()` is
only called on query feeds (verified by grepping for all of its
occurrences and ensuring they're all wrapped in `if
(feed->is_query_feed())`).

der-lyse/newsboat,newsboat/newsboat,der-lyse/newsboat,newsboat/newsboat,der-lyse/newsboat,newsboat/newsboat,newsboat/newsboat,newsboat/newsboat,newsboat/newsboat,der-lyse/newsboat,newsboat/newsboat,der-lyse/newsboat,der-lyse/newsboat,newsboat/newsboat,der-lyse/newsboat,der-lyse/newsboat