Python version 2.4 (improperly, IMHO) does not have `const' on the docstring in
PyTypeObject.  This caused a compiler error because we generate all of our
docstrings with const on them.  I put a conditional in the generation
which causes us to only use const if the user has Python 2.5.

git-svn-id: http://visit.ilight.com/svn/visit/trunk/src@4799 18c085ea-50e0-402c-830e-de6fd14e8384