The current approach to capture the Python version is fragile, as it
was demonstrated by a very specific build of Python 3 on Fedora 29
that, under non-interactive shells would print multiline version
information.

The (badly) stripped version output would be sent to config-host.mak,
producing bad syntax and rendering the makefiles unusable.  Now, the
Python versions is printed by configure, but only a simple (and better
controlled variable) indicating whether the build system is using
Python 2 is kept on config-host.mak.

Signed-off-by: Cleber Rosa <crosa@redhat.com>

Message-Id: <20190826155832.17427-1-crosa@redhat.com>
Reviewed-by: Tony Nguyen <tony.nguyen@bt.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>