pgsql: Patch some corner-case bugs in pl/python.

Patch some corner-case bugs in pl/python.

Dave Malcolm of Red Hat is working on a static code analysis tool for
Python-related C code. It reported a number of problems in plpython,
most of which were failures to check for NULL results from object-creation
functions, so would only be an issue in very-low-memory situations.

Patch in HEAD and 9.1. We could go further back but it's not clear that
these issues are important enough to justify the work.

Jan Urbański

Branch
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REL9_1_STABLE

Details
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http://git.postgresql.org/pg/commitdiff/0cb4a0bfb80c7d75c745faf3597bed5c3f9a3c49

Modified Files
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src/pl/plpython/plpython.c | 29 ++++++++++++++++++++++++++---
1 files changed, 26 insertions(+), 3 deletions(-)