Doesn't handle django.contrib.contenttypes.generic.GenericRelation

[Kevin McDermott]

  File "/home/kevin/src/branch/lib/python2.7/site-packages/django_factory/factory.py", line 493, in make_one
    return self._create_one(model, True, [], attrs)
  File "/home/kevin/src/branch/lib/python2.7/site-packages/django_factory/factory.py", line 413, in _create_one
    instance, m2m_dict, fk_dict = self._generate_instance(model, save, attrs, not_including)
  File "/home/kevin/src/branch/lib/python2.7/site-packages/django_factory/factory.py", line 296, in _generate_instance
    use, value = self._generate_plain_value(model, field, attrs)
  File "/home/kevin/src/branch/lib/python2.7/site-packages/django_factory/factory.py", line 255, in _generate_plain_value
    value = self.generate_value(field)
  File "/home/kevin/src/branch/lib/python2.7/site-packages/django_factory/factory.py", line 548, in generate_value
    raise TypeError("Can't generate value for field: %s" % field)
TypeError: Can't generate value for field: <django.contrib.contenttypes.generic.GenericRelation: bugs>

[Kevin McDermott (bigkevmcd)]

Personally, I'd be happy if it just ignored these in _generate_instance.