[Distutils] zc.buildout: the extended-by option

[Thomas Lotze]

Hi,

the buildout section used to have an option named "extended-by" that has
been deprecated for quite a while. The option is not (no longer?) present
in documentation and tests and the only thing left of it is the
implementation and a check that is supposed to result in a deprecation
warning. However, there's a bug in the implementation that looks as if it
was caused by some refactoring, which would cause a NameError to be raised
instead of the deprecation warning being printed.

To me, this looks as if it was safe to just remove any traces of the
option, including the buggy implementation. The only downside would be
that configurations which still use the option would fail silently
instead of raising the NameError. I don't consider this to be of much
importance in practice, but before going ahead and removing code, I wanted
to give people a chance to disagree. Thank you.

-- 
Thomas