python - be: Only do handler based Python identification.

Log Message:
-----------
Only do handler based Python identification. While LanguageOid based
identification avoids hitting the fmgrinfo once, it's not a significant enough
improvement to justify special casing it. Multiple Languages can be bound to
the handler, so only keeping track of one language only provides an optimization
for that language(first loid).

Modified Files:
--------------
be/include/pypg:
cis.h (r1.4 -> r1.5)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/python/be/include/pypg/cis.h.diff?r1=1.4&r2=1.5)
be/src:
function.c (r1.7 -> r1.8)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/python/be/src/function.c.diff?r1=1.7&r2=1.8)
module.c (r1.19 -> r1.20)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/python/be/src/module.c.diff?r1=1.19&r2=1.20)
pl.c (r1.24 -> r1.25)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/python/be/src/pl.c.diff?r1=1.24&r2=1.25)