buildtools: Ignore exact Python version for ABI checking

buildtools: Ignore exact Python version for ABI checking

Utilities for Python libraries are built for a specific Python
version. Starting with Python 3, the Python version is recorded
in the shared library filename as an ABI tag, e.g. "pytalloc.cpython-34m.so.
The exact version doesn't matter for Samba's ABI check.
Replace the ABI tag with a simpler one that just records the major
version of Python.

Signed-off-by: Petr Viktorin <pviktori@redhat.com>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
Reviewed-by: Stefan Metzmacher <metze@samba.org>
Autobuild-User(master): Stefan Metzmacher <metze@samba.org>
Autobuild-Date(master): Sun Nov  1 01:09:06 CET 2015 on sn-devel-104