[mod_python] SetEnv and add_common_vars()

When I use SetEnv in my apache conf file, it causes a lot of the
environment variables (such as DOCUMENT_ROOT) to disappear that
add_common_vars() normally would set.

The only workaround I have is to put the SetEnv statements in a
different <Directory> block than the directory with the files served by
mod_python.

Is this a bug in mod_env or mod_python? Is there a better way to fix
this?

-Edwin