Add oslo.config.opts entrypoint for audit middleware options

... so that each service using the audit middleware can include these
parameters in .conf file generated by oslo-config-generator by adding
that entrypoint to the command.

Closes-Bug: #1939632
Change-Id: Ied954c633570c51af9504514ffed18e12de8caac

keystonemiddleware/audit/__init__.py

@@ -92,7 +92,7 @@ class AuditMiddleware(object):
         self._application = app
         self._conf = config.Config('audit',
                                    AUDIT_MIDDLEWARE_GROUP,
-                                   _list_opts(),
+                                   list_opts(),
                                    conf)
         global _LOG
         _LOG = logging.getLogger(conf.get('log_name', __name__))
@@ -165,7 +165,7 @@ class AuditMiddleware(object):
         return response
 
 
-def _list_opts():
+def list_opts():
     """Return a list of oslo_config options available in audit middleware.
 
     The returned list includes all oslo_config options which may be registered

setup.cfg

@@ -32,6 +32,7 @@ setup-hooks =
 [entry_points]
 oslo.config.opts =
     keystonemiddleware.auth_token = keystonemiddleware.auth_token._opts:list_opts
+    keystonemiddleware.audit = keystonemiddleware.audit:list_opts
 
 paste.filter_factory =
     auth_token = keystonemiddleware.auth_token:filter_factory