pgsql: Mop-up for nulls-in-arrays patch: fix some places that access

Log Message:
-----------
Mop-up for nulls-in-arrays patch: fix some places that access array
contents directly.

Modified Files:
--------------
pgsql/contrib/dblink:
dblink.c (r1.48 -> r1.49)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/dblink/dblink.c.diff?r1=1.48&r2=1.49)
pgsql/contrib/tsearch2:
rank.c (r1.13 -> r1.14)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/tsearch2/rank.c.diff?r1=1.13&r2=1.14)
ts_cfg.c (r1.15 -> r1.16)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/tsearch2/ts_cfg.c.diff?r1=1.15&r2=1.16)
pgsql/contrib/tsearch2/snowball:
header.h (r1.5 -> r1.6)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/tsearch2/snowball/header.h.diff?r1=1.5&r2=1.6)
pgsql/src/backend/utils/adt:
acl.c (r1.128 -> r1.129)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/adt/acl.c.diff?r1=1.128&r2=1.129)
varlena.c (r1.139 -> r1.140)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/adt/varlena.c.diff?r1=1.139&r2=1.140)
pgsql/src/include/utils:
acl.h (r1.87 -> r1.88)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/utils/acl.h.diff?r1=1.87&r2=1.88)
pgsql/src/pl/plpgsql/src:
pl_exec.c (r1.155 -> r1.156)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/pl/plpgsql/src/pl_exec.c.diff?r1=1.155&r2=1.156)