RFC: fix atexit.register

[Eli Zaretskii]

> From: Tom Tromey <tromey@redhat.com>
> Date: Thu, 06 Sep 2012 09:43:26 -0600
> 
> A user on irc reported that Python's atexit.register did not work
> properly in gdb.
> 
> This patch fixes the problem by installing a final cleanup that calls
> Py_Finalize.
> 
> Regression tested on x86-64 F16.
> New test case included.
> 
> Tom
> 
> 	* NEWS: Update.
> 	* python/python.c (finalize_python): New function.
> 	(_initialize_python): Make a final cleanup.
> 
> 	* gdb.python/python.exp: Test atexit.register.

OK for the NEWS part.

Thanks.