swig: python variant should depend on python_select

[ram@…]

The python variant of swig currently depends explicitly on python25, where all it actually needs is a python as the installed product doesn't actually depend on a specific python version. It would therefore make more sense if the dependency for the python variant was python_select instead.

[ram@…]

depend on python_select for python variant

[raimue@…]

A dependency on python_select does not make sense because it does not depend on any python port. So an installation of swig without a previous python install will fail with this patch.

I would recommend to create variants for +python24 and +python25.

[ram@…]

It won't, python_select adds a symlink to the system python as /opt/local/bin/python and that is good enough to install swig and then nothing will break if python_select is used after to point to a different python.