BUG #7831: user defined-aggregated don't set initcond to null when unspecified, instead uses its first argument

The following bug has been logged on the website:

Bug reference:      7831
Logged by:          Abel Abraham Camarillo Ojeda
Email address:      acamari@verlet.org
PostgreSQL version: 9.1.2
Operating system:   OpenBSD-5.1/amd64.MP
Description:        =


user defined-aggregated don't set initcond to null when unspecified, instead
uses its first argument.

To reproduce:

$ =

$ cat > /tmp/sql
create or replace function
_foo (state double precision, i double precision)
returns double precision language sql immutable strict as
$$
        select 999::double precision;
$$;

create aggregate foo (double precision) (
    sfunc =3D _foo,
    stype =3D double precision
);

select foo(0);
$ =

$ psql -U postgres template1 < /tmp/sql
CREATE FUNCTION
CREATE AGGREGATE
 foo =

-----
   0
(1 row)

$
$ psql -U postgres template1
psql (9.1.2)
Type "help" for help.

template1=3D# =