Contact view can access ``smart_form_group`` before it's defined.

```
Stacktrace (most recent call last):

(4 additional frame(s) were not displayed)
...
  File "django/utils/decorators.py", line 91, in _wrapped_view
    response = view_func(request, *args, **kwargs)
  File "go/contacts/views.py", line 133, in _group
    return _smart_group(request, contact_store, group)
  File "django/utils/decorators.py", line 91, in _wrapped_view
    response = view_func(request, *args, **kwargs)
  File "django/contrib/auth/decorators.py",
  line 25, in _wrapped_view
    return view_func(request, *args, **kwargs)
  File "go/contacts/views.py", line 315, in _smart_group
    'group_form': smart_group_form,
```
I think this is an unhandled error path in the ``if`` statement higher up in the code.
I think the ``_remove`` and ``_complete_contact_upload`` paths can also potentially not set ``group_form``.