This update for python-rpm-macros fixes the following issues:

- Fix skip_python2 in environment where python2 is not actually present.
- Introduce smarter buildset support.
- Fix %python_files on non-standard build sets.
- Introduce %python_for_executables in favor of magically taking "last python in %pythons".
- Fix %license tag handling.

This update was imported from the SUSE:SLE-12:Update update project.