[PATCH] Remove Python 2.4 and 2.5 support

[Eli Zaretskii]

> From: Pedro Alves <palves@redhat.com>
> Date: Wed, 27 Feb 2019 19:08:52 +0000
> 
> On 02/26/2019 07:53 PM, Tom Tromey wrote:
> > This removes all the remainings spots I could find that work around
> > issues in Python 2.4 and 2.5.
> > 
> > I don't have a good way to test that Python 2.6 still works.
> > 
> > Tested by the buildbot.
> 
> Great, thanks for doing this.

FYI, I've built the pretest of GDB 8.3 with Python 2.6.  The build was
clean wrt Python-related sources, and the little testing I did
indicates that it works fine.