pgsql: Put back blessing of record-function tupledesc, which I removed

Log Message:
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Put back blessing of record-function tupledesc, which I removed in a
fit of over-optimization.

Modified Files:
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pgsql/src/backend/executor:
nodeFunctionscan.c (r1.32 -> r1.33)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/executor/nodeFunctionscan.c.diff?r1=1.32&r2=1.33)