After 578b2297 / the removal of WITH OIDS support, older dump files
containing
    SET default_with_oids = false;
either report unnecessary errors (as the subsequent tables have no
oids) or even fail to restore entirely (when using transaction mode).
To avoid that, re-add the GUC, but don't allow setting it to true.

Per complaint from Tom Lane.

Author: Amit Khandekar, editorialized by me
Discussion: https://postgr.es/m/CAJ3gD9dZyxrtL0rJfoNoOj6v7fJSDaXBngi9wy5XU8m-ioXhAA@mail.gmail.com