BUG #2299: pg_dump error w/ renamed primary keys

The following bug has been logged online:

Bug reference:      2299
Logged by:          Gavin Scott
Email address:      gavin@planetacetech.com
PostgreSQL version: 8.1.3
Operating system:   fedora core 4
Description:        pg_dump error w/ renamed primary keys
Details:

If you rename a primary key, pg_dump tries to recreate it with the original
name.  Here is how to recreate:

[postgres81@boll ~]$ createdb bug
CREATE DATABASE
[postgres81@boll ~]$ psql bug << EOF
> CREATE TABLE foo ( id integer );
> ALTER TABLE foo ADD CONSTRAINT foo_pkey PRIMARY KEY (id);
> ALTER TABLE foo_pkey RENAME TO bar_pkey;
> EOF
CREATE TABLE
NOTICE:  ALTER TABLE / ADD PRIMARY KEY will create implicit index "foo_pkey"
for table "foo"
ALTER TABLE
ALTER TABLE
[postgres81@boll ~]$ echo '\d foo' | psql bug
      Table "public.foo"
 Column |  Type   | Modifiers
--------+---------+-----------
 id     | integer | not null
Indexes:
    "bar_pkey" PRIMARY KEY, btree (id)

[postgres81@boll ~]$ pg_dump bug | grep -B 1 -i key
--
-- Name: foo_pkey; Type: CONSTRAINT; Schema: public; Owner: postgres81;
Tablespace:
--
ALTER TABLE ONLY foo
    ADD CONSTRAINT foo_pkey PRIMARY KEY (id);