Fix task_manager process_event docstring

It became a warning treated as error recently.
Also skips tests directory while building docs.

Change-Id: Ie95814ae42c35be5f5dee956a71bea9b60d90ba9

doc/source/conf.py

@@ -49,7 +49,9 @@ apidoc_output_dir = 'contributor/api'
 apidoc_excluded_paths = [
     'db/sqlalchemy/alembic/env'
     'db/sqlalchemy/alembic/versions/*',
-    'drivers/modules/ansible/playbooks*']
+    'drivers/modules/ansible/playbooks*',
+    'tests',
+]
 apidoc_separate_modules = True
 
 repository_name = 'openstack/ironic'

ironic/conductor/task_manager.py

@@ -426,8 +426,8 @@ class TaskManager(object):
 
         :param event: the name of the event to process
         :param callback: optional callback to invoke upon event transition
-        :param call_args: optional *args to pass to the callback method
-        :param call_kwargs: optional **kwargs to pass to the callback method
+        :param call_args: optional args to pass to the callback method
+        :param call_kwargs: optional kwargs to pass to the callback method
         :param err_handler: optional error handler to invoke if the
                 callback fails, eg. because there are no workers available
                 (err_handler should accept arguments node, prev_prov_state, and