Cope with circularities involving a view's ON SELECT rule. I originally

Cope with circularities involving a view's ON SELECT rule.  I originally
thought there couldn't be any, but the folly of this was exposed by an
example from andrew@supernews.com 5-Dec-2004.  The patch applies the
identical logic already used for table constraints and defaults to ON
SELECT rules, so I have reasonable confidence in it even though it might
look like complicated logic.