[IronPython] Assertion failure in IPy 2.6 while running Django

[Jeff Hardy]

The assertion is on line 91 of PythonFunction.Generated.cs (as of
r49699, anyway): mi != null. Why mi is null I have no idea.

The smallest repro I've found still requires Django (any recent
checkout should do):

>>> from django.db import models
>>> message = models.TextField('message')

If I had the following __init__ function to TextField the problem goes away:
def __init__(self, *args, **kwargs):
        Field.__init__(self, *args, **kwargs)

- Jeff