Fixed django#19391 -- Oracle specific failure in tests

The failure was caused by using None as a choice for a CharField. To avoid Oracle's "" <-> NULL handling the field type was changed to IntegerField.

Author: akaariai

tests/regressiontests/admin_views/models.py

@@ -662,5 +662,5 @@ class Simple(models.Model):
  """
 
 class Choice(models.Model):
- choice = models.CharField(max_length=1, blank=True, null=True,
- choices=(('y','Yes'), ('n','No'), (None, 'No opinion')))
+ choice = models.IntegerField(blank=True, null=True,
+ choices=((1, 'Yes'), (0, 'No'), (None, 'No opinion')))