Removal decorator does not work on classes using super()

[Julien Danjou]

Traceback (most recent call last):
  File "debtcollector/tests/test_deprecation.py", line 306, in test_class_removal_super
    Foobar()
  File "debtcollector/removals.py", line 101, in wrapper
    return f(*args, **kwargs)
  File "debtcollector/tests/test_deprecation.py", line 304, in __init__
    super(Foobar, self).__init__()
TypeError: must be type, not FunctionWrapper