Bug: If a Member had the hide_deleted_posts option turned on and did a
two tag search, no pages would show up.
Cause: The hide_deleted_posts option implicitly adds the -status:deleted
tag, but this tag wasn't considered a free metatag, so this caused
Post.fast_count to fail and return zero because the search was treated
as a three tag search.
ref: https://danbooru.donmai.us/forum_topics/16829
cacc32740c