pgsql: Update UNION/INTERSECT/EXCEPT ORDER BY error wording for

Log Message:
-----------
Update UNION/INTERSECT/EXCEPT ORDER BY error wording for
expressions/functions.

Modified Files:
--------------
pgsql/src/backend/parser:
analyze.c (r1.356 -> r1.357)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/parser/analyze.c.diff?r1=1.356&r2=1.357)