pgsql: PL/Python: Report argument parsing errors using exceptions

PL/Python: Report argument parsing errors using exceptions

Instead of calling PLy_elog() for reporting Python argument parsing
errors, generate appropriate exceptions.  This matches the existing plpy
functions and is more consistent with the behavior of the Python
argument parsing routines.

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/3a4a33ad49e7887b104a29323e4ea625d164a139

Modified Files
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src/pl/plpython/expected/plpython_ereport.out | 28 +++++++++++++++++++--------
src/pl/plpython/plpy_plpymodule.c             | 23 +++++++++++++++++-----
2 files changed, 38 insertions(+), 13 deletions(-)