pgsql: Fix longstanding oversight in ruleutils.c: it doesn't regurgitate

Log Message:
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Fix longstanding oversight in ruleutils.c: it doesn't regurgitate
a FOR UPDATE clause, if one is present.

Modified Files:
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pgsql/src/backend/utils/adt:
ruleutils.c (r1.196 -> r1.197)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/adt/ruleutils.c.diff?r1=1.196&r2=1.197)