Fixed #21302 -- Fixed unused imports and import *.

tests/admin_scripts/broken_app/models.py

@@ -1 +1 @@
-from django.db import modelz
+from django.db import modelz  # NOQA

tests/admin_scripts/complex_app/models/bar.py

@@ -1,7 +1,5 @@
 from django.db import models
 
-from ..admin import foo
-
 
 class Bar(models.Model):
     name = models.CharField(max_length=5)

tests/admin_scripts/simple_app/models.py

@@ -1 +1,3 @@
 from ..complex_app.models.bar import Bar
+
+__all__ = ['Bar']