[mod_python] 2.6.4

There is a 2.6.4 available for download now. This is a bugfix release only
and has no new features. It should fix the problem that would manifest
itself by Internal Server Errors and "Dispatch() returned nothing" in the
error log. 

If you're using DSO, you will only need to replace mod_python.so. There
are no changes in the python libraries. I do recommend that you upgrade,
especially is you use multuple virtual servers/interpreters.

Windows users do not need to worry about upgrading, they were not affected
by the problem.

The bug had to do with misplaced #ifdef WITH_THREAD which caused
mod_python not to switch subinterpreters correctly and make python run in
restriced mode, in which __dict__ and some other things are not available.

--
  Gregory (Grisha) Trubetskoy
       grisha at modpython.org