BUG #7748: "drop owned by" fails with error message: "unrecognized object class: 1262"

The following bug has been logged on the website:

Bug reference: 7748
Logged by: Thomas Kellerer
Email address: spam_eater(at)gmx(dot)net
PostgreSQL version: 9.2.2
Operating system: Windows XP, 32bit
Description:

Using "drop owned by someuser" in 9.2.2 fails with the error
"unrecognized object class: 1262"

This is what happens on the commandline. The PostgreSQL cluster was
initialized right before running these steps using the command:

initdb -D pgdata --lc-messages=English -U postgres -E UTF8 -A md5

This is what happens when using "drop owned by":

c:\etc\postgres-9.2>psql
psql (9.2.2)
Type "help" for help.

postgres=# create user testuser with password 'secret';
CREATE ROLE
postgres=# create database testdb owner testuser;
CREATE DATABASE
postgres=# \q

c:\etc\postgres-9.2>psql -U testuser testdb
psql (9.2.2)
Type "help" for help.

testdb=> create table foobar (id integer);
CREATE TABLE
testdb=> drop owned by testuser;
ERROR: unrecognized object class: 1262
postgres=# select version();
version
-------------------------------------------------------------
PostgreSQL 9.2.2, compiled by Visual C++ build 1600, 32-bit
(1 row)

Dropping the objects manually works without problems.