Fixed #28750 -- Allowed models to define Meta.manager_inheritance_from_future for backwards compatibility.

Refs 631f4ab061.

tests/model_meta/test_manager_inheritance_from_future.py

@@ -0,0 +1,15 @@
+from django.db import models
+from django.test import SimpleTestCase
+from django.test.utils import isolate_apps
+
+
+@isolate_apps('model_meta')
+class TestManagerInheritanceFromFuture(SimpleTestCase):
+    def test_defined(self):
+        """
+        Meta.manager_inheritance_from_future can be defined for backwards
+        compatibility with Django 1.11.
+        """
+        class FuturisticModel(models.Model):
+            class Meta:
+                manager_inheritance_from_future = True  # No error raised.