pgsql: Fix backpatching error in recent patch for ALTER USER f RESET ALL

Log Message:
-----------
Fix backpatching error in recent patch for ALTER USER f RESET ALL behavior.
The argument list for array_set() changed in 8.2 (in connection with allowing
nulls in arrays) but the newer argument list was used in the patches applied
to 8.1 and 8.0 branches.  The patch for 7.4 was OK though.  Per compiler
warnings.

Tags:
----
REL8_0_STABLE

Modified Files:
--------------
    pgsql/src/backend/utils/misc:
        guc.c (r1.252.4.10 -> r1.252.4.11)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/misc/guc.c?r1=1.252.4.10&r2=1.252.4.11)