python - be: Use package_dir appropriately, removing some kludge.

Log Message:
-----------
Use package_dir appropriately, removing some kludge.
No longer depend on the module path to provide the destination directory. For
now, it's always relative to site-packages. However, it should rely on
install_lib.
(Back to relying on layout being installed/accessible)

Modified Files:
--------------
be:
setup.py (r1.11 -> r1.12)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/python/be/setup.py.diff?r1=1.11&r2=1.12)
be/lib:
ldistutils.py (r1.5 -> r1.6)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/python/be/lib/ldistutils.py.diff?r1=1.5&r2=1.6)
be/src:
module.c (r1.14 -> r1.15)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/python/be/src/module.c.diff?r1=1.14&r2=1.15)