Proposal: Drop GDB support for Python versions < 2.6

[Kevin Buettner <kevinb@redhat.com>]

I want to drop support in GDB for Python versions 2.5 and lower.

I've proposed two patches which use facilities that are only present
in Python 2.6 and later.  To be clear, these mechanisms are also
present in Python 2.7 and 3.X.  Python documentation encourages use of
these newer facilities over the older ones.

My patches can be found here:

https://sourceware.org/ml/gdb-patches/2019-02/msg00311.html

https://sourceware.org/ml/gdb-patches/2019-02/msg00314.html

The latter patch provides a detailed rationale for dropping support
for older versions of Python.  Here is a brief summary:

Python 2.6 was first released in Oct, 2008.  Five years later, in Oct,
2013, a final security release was made along with the announcement
that support for Python 2.6 has ended.  That being the case, it seems
reasonable for GDB to end support for all Python versions prior to
Python 2.6.

Going even further, since 2.6 is no longer supported by the Python
community, I'd also be okay with saying that GDB only supports Python
2.7 and Python 3.X.

Comments?