and drastically simplify it. The behavior is similar enough for
most cases, except:
* regular expression operators are no longer supported. It's not
hard to re-add them. As they're not needed right now, they can
be temporarily removed
* virtual attributes like Packet-Src-IP-Address are not supported
Again, this isn't terribly difficult to re-add. But once the
Packet-* attributes are moved to Net.* attributes, then any
virtual attribute comparisons become much less useful.
The remainder are Virtual-Server, Request-Processing-Stage,
and Module-Return-Code. Those could arguably all be moved to
realized attributes in the control list. And be made immutable,
so that "unlang" can't change them.