Fix != operations on lazy objects.

django/utils/functional.py

@@ -346,6 +346,7 @@ class SimpleLazyObject(LazyObject):
     # care about this (especially in equality tests)
     __class__ = property(new_method_proxy(operator.attrgetter("__class__")))
     __eq__ = new_method_proxy(operator.eq)
+    __ne__ = new_method_proxy(operator.ne)
     __hash__ = new_method_proxy(hash)
     __bool__ = new_method_proxy(bool)       # Python 3
     __nonzero__ = __bool__                  # Python 2

tests/utils_tests/test_simplelazyobject.py

@@ -152,3 +152,12 @@ class TestUtilsSimpleLazyObject(TestCase):
             SimpleLazyObject(None)
         finally:
             sys.settrace(old_trace_func)
+
+    def test_not_equal(self):
+        lazy1 = SimpleLazyObject(lambda: 2)
+        lazy2 = SimpleLazyObject(lambda: 2)
+        lazy3 = SimpleLazyObject(lambda: 3)
+        self.assertEqual(lazy1, lazy2)
+        self.assertNotEqual(lazy1, lazy3)
+        self.assertTrue(lazy1 != lazy3)
+        self.assertFalse(lazy1 != lazy2)