Minor argument changes.

src/flake8/main/application.py

@@ -93,7 +93,7 @@ class Application(object):
         #: The parsed diff information
         self.parsed_diff = {}
 
-    def parse_preliminary_options_and_args(self, argv):
+    def parse_preliminary_options_and_args(self, argv=None):
         """Get preliminary options and args from CLI, pre-plugin-loading.
 
         We need to know the values of a few standard options and args now, so

src/flake8/plugins/manager.py

@@ -237,7 +237,7 @@ class PluginManager(object):  # pylint: disable=too-few-public-methods
     """Find and manage plugins consistently."""
 
     def __init__(self, namespace,
-                 local_plugins=None, verify_requirements=False):
+                 verify_requirements=False, local_plugins=None):
         """Initialize the manager.
 
         :param str namespace: