pgsql: Fix leakage of proc-related storage in plpython's inline handler.

Log Message:
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Fix leakage of proc-related storage in plpython's inline handler.
Per report from Andres Freund.

Modified Files:
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pgsql/src/pl/plpython:
plpython.c (r1.142 -> r1.143)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/pl/plpython/plpython.c?r1=1.142&r2=1.143)