Fix a bug where searching for a negated tag inside the modqueue would show
active posts.
The bug was that in a search like this:
Post.in_modqueue.user_tag_match("-solo")
The `in_modqueue` condition would get sucked inside the tag search and negated
when we tried to apply the negation operator to the "solo" tag. So effectively
the `in_modqueue` condition would get negated and we would end up searching for
everything not in the modqueue.
4c03ea5be3