Added multi_db=True to test cases that access the 'other' db connection.

Fixed a failure in the context processors tests when running in
reverse on MySQL due to an extra query after refs #27683.

tests/migrations/test_loader.py

@@ -11,6 +11,7 @@ class RecorderTests(TestCase):
     """
     Tests recording migrations as applied or not.
     """
+    multi_db = True
 
     def test_apply(self):
         """