pgsql: Additional fixes for large object access control.

Log Message:
-----------
Additional fixes for large object access control.
Use pg_largeobject_metadata.oid instead of pg_largeobject.loid
to enumerate existing large objects in pg_dump, pg_restore, and
contrib modules.

Modified Files:
--------------
    pgsql/contrib/lo:
        lo_test.sql (r1.5 -> r1.6)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/contrib/lo/lo_test.sql?r1=1.5&r2=1.6)
    pgsql/contrib/vacuumlo:
        vacuumlo.c (r1.42 -> r1.43)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/contrib/vacuumlo/vacuumlo.c?r1=1.42&r2=1.43)
    pgsql/src/bin/pg_dump:
        pg_backup_archiver.c (r1.176 -> r1.177)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/bin/pg_dump/pg_backup_archiver.c?r1=1.176&r2=1.177)
        pg_backup_archiver.h (r1.82 -> r1.83)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/bin/pg_dump/pg_backup_archiver.h?r1=1.82&r2=1.83)
        pg_backup_db.c (r1.84 -> r1.85)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/bin/pg_dump/pg_backup_db.c?r1=1.84&r2=1.85)
        pg_backup_null.c (r1.22 -> r1.23)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/bin/pg_dump/pg_backup_null.c?r1=1.22&r2=1.23)
        pg_dump.c (r1.555 -> r1.556)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/bin/pg_dump/pg_dump.c?r1=1.555&r2=1.556)
    pgsql/src/test/regress/expected:
        privileges.out (r1.52 -> r1.53)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/expected/privileges.out?r1=1.52&r2=1.53)
    pgsql/src/test/regress/sql:
        privileges.sql (r1.31 -> r1.32)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/sql/privileges.sql?r1=1.31&r2=1.32)