Remove unused transaction handling

apps/app_registry/models.py

@@ -23,7 +23,6 @@ class App(object):
         try:
             app_module = import_module(app_name)
         except ImportError:
-            transaction.rollback
             logger.error('Unable to import app: %s' % app_name)
         else:
             logger.debug('Trying to import registry from: %s' % app_name)