Fixed #7698 -- Handle '0' correctly when used as the upper bound of a slice.

Based on a patch from enoksrd.


git-svn-id: http://code.djangoproject.com/svn/django/trunk@7885 bcc190cf-cafb-0310-a4f2-bffc1f526a37

tests/regressiontests/queries/models.py

@@ -810,5 +810,9 @@ used in lookups.
 >>> Item.objects.filter(created__in=[time1, time2])
 [<Item: one>, <Item: two>]
 
+Bug #7698 -- People like to slice with '0' as the high-water mark.
+>>> Item.objects.all()[0:0]
+[]
+
 """}