BUG #15546: alter large object n owner to new owner

The following bug has been logged on the website:

Bug reference:      15546
Logged by:          Stefan Kadow
Email address:      git17@ska67.de
PostgreSQL version: 9.6.10
Operating system:   Debian 9.6 (Stretch)
Description:

Documentation describes:
ALTER LARGE OBJECT large_object_oid OWNER TO { new_owner | CURRENT_USER |
SESSION_USER }
You must be superuser or owner of the large object to use ALTER LARGE
OBJECT.

If you want to use this statement for assigning a "new owner", you have to
be a superuser.
If you are only the owner of the large object, you receive an error message
Postgresql-Error 42501 saying that you must be in the role of the "new
owner".