Merge pull request #17094 from edx/revert-17030-douglashall/ENT-779_drop_existing_session_migration

Revert "ENT-779 Remove ProviderConfig.drop_existing_session field from DB."

common/djangoapps/third_party_auth/migrations/0014_auto_20171222_1233.py

@@ -1,26 +0,0 @@
-# -*- coding: utf-8 -*-
-from __future__ import unicode_literals
-
-from django.db import migrations, models
-
-
-class Migration(migrations.Migration):
-
-    dependencies = [
-        ('third_party_auth', '0013_sync_learner_profile_data'),
-    ]
-
-    operations = [
-        migrations.RemoveField(
-            model_name='ltiproviderconfig',
-            name='drop_existing_session',
-        ),
-        migrations.RemoveField(
-            model_name='oauth2providerconfig',
-            name='drop_existing_session',
-        ),
-        migrations.RemoveField(
-            model_name='samlproviderconfig',
-            name='drop_existing_session',
-        ),
-    ]

common/djangoapps/util/tests/test_db.py

@@ -237,4 +237,10 @@ class MigrationTests(TestCase):
         out = StringIO()
         call_command('makemigrations', dry_run=True, verbosity=3, stdout=out)
         output = out.getvalue()
-        self.assertIn('No changes detected', output)
+        # Temporarily disable this check so we can remove
+        # the ProviderConfig.drop_existing_session field.
+        # We will restore this check once the code referencing
+        # this field has been deleted/released and a migration
+        # for field removal has been added.
+        if 'Remove field' not in output:
+            self.assertIn('No changes detected', output)