pgsql: Fix memory leak in rtdosplit, per report from Clive Page.

Log Message:
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Fix memory leak in rtdosplit, per report from Clive Page.

Tags:
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REL8_0_STABLE

Modified Files:
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pgsql/src/backend/access/rtree:
rtree.c (r1.85 -> r1.85.4.1)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/access/rtree/rtree.c.diff?r1=1.85&r2=1.85.4.1)