pgsql: Avoid unnecessary call of rangeTableEntry_used() for the result

Log Message:
-----------
Avoid unnecessary call of rangeTableEntry_used() for the result relation
of a query.

Modified Files:
--------------
pgsql/src/backend/rewrite:
rewriteHandler.c (r1.151 -> r1.152)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/rewrite/rewriteHandler.c.diff?r1=1.151&r2=1.152)