Get rid of unused NoOpMigrationModules

cms/envs/test.py

@@ -21,7 +21,6 @@ from django.utils.translation import ugettext_lazy
 from path import Path as path
 
 from openedx.core.lib.derived import derive_settings
-from util.db import NoOpMigrationModules
 
 from xmodule.modulestore.modulestore_settings import update_module_store_settings
 

common/djangoapps/util/db.py

@@ -151,16 +151,3 @@ def generate_int_id(minimum=0, maximum=MYSQL_MAX_INT, used_ids=None):
         cid = random.randint(minimum, maximum)
 
     return cid
-
-
-class NoOpMigrationModules(object):
-    """
-    Return invalid migrations modules for apps. Used for disabling migrations during tests.
-    See https://groups.google.com/d/msg/django-developers/PWPj3etj3-U/kCl6pMsQYYoJ.
-    """
-
-    def __contains__(self, item):
-        return True
-
-    def __getitem__(self, item):
-        return None

lms/envs/test.py

@@ -34,7 +34,6 @@ from xmodule.modulestore.modulestore_settings import update_module_store_setting
 
 from .common import *
 
-from util.db import NoOpMigrationModules  # pylint: disable=wrong-import-order
 from util.testing import patch_sessions, patch_testcase  # pylint: disable=wrong-import-order
 
 # This patch disables the commit_on_success decorator during tests