Attached is a patch to fix some pychecker complaints Neal Norwitz
uncovered.  All involved tests pass.  Submitting patch simply because
we're past beta3.

It doubt many people are inheriting from the classes that are changed to
new-style in the patch, but I thought it was policy that we didn't
change that until 3.0 "just in case".

I can see where that might be a problem.  If that's the case I suspect 
those property attributes should be changed.  OTOH, do properties work on 
classic classes?

Read-only properties on old-style classes seem to work (though I don't
know if that is an implementation accident), insofar it seems harmless
not to apply this patch.

No, they don't work correctly. Readonly properties in old style classes
aren't readonly:

>>> class Example:
...     @property
...     def spam(self):
...         return "spam"
...
>>> example = Example()
>>> example.spam
'spam'
>>> example.spam = "egg"
>>> example.spam
'egg'

Ah yes. But still, I'd call that harmless. Assigning to attributes
you're not supposed to assign to is detrimental in many cases.

If it's only to please pychecker, then I don't think we should make this
change. It's potential gratuitous breakage, especially if people
subclass those classes.

I agree with Antoine, so I'm just going to close this as rejected.
There's little benefit in it, but there is potential harm.