The readline module is part of Python itself, but it must be required
explicitly on newer distributions (16.0, Factory). However, Python
packages in older distributions (15.x and earlier) do not have the
corresponding Provides. :-(
Solve it by Build-requiring %pythons. Yes, it does bring a lot of
unneded stuff into the build environment...
Signed-off-by: Petr Tesarik <ptesarik@suse.com>