Off topic:
Here would be a with-expression or inline with (like the inline if) handy:
spec_file.write('''
%%changelog
* %s Maintainer Name <maintainer at example.com>
''' % (time.strftime('%a %b %d %Y') with localectx(locale.LC_TIME,('en','UTF8'))))
However, this would be a very long line. Not very clean code.
-panzi