adding ENGINE back

playbooks/roles/edxapp/defaults/main.yml

@@ -161,6 +161,7 @@ edxapp_generic_auth_config:  &edxapp_generic_auth
       DOC_STORE_CONFIG: *edxapp_generic_default_docstore
   DATABASES:
     default:
+      ENGINE: 'django.db.backends.mysql'
       NAME: $EDXAPP_MYSQL_DB_NAME
       USER: $EDXAPP_MYSQL_USER
       PASSWORD: $EDXAPP_MYSQL_PASSWORD