Fix vacuum analyze error.

vacuum analyze on pg_type fails if bogus entries remain in pg_operator.
Here is a sample script to reproduce the problem.

drop table t1;
create table t1(i int);
drop function foo(t1,t1);
create function foo(t1,t1) returns bool as 'select true' language 'sql';
create operator = (
	leftarg = t1,
	rightarg = t1,
	commutator = =,
	procedure = foo
	);
drop table t1;
vacuum analyze;