python - be: Rely on the constant being defined rather than the version

Log Message:
-----------
Rely on the constant being defined rather than the version that it is thought to
be defined with.

Modified Files:
--------------
be/src:
constants.c (r1.6 -> r1.7)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/python/be/src/constants.c.diff?r1=1.6&r2=1.7)