Remove fallback to DEFAULT section

It was added 9 years ago in 0.1.0 release[1].

[1] ad2c5dd1f8

Change-Id: Ic7ea71de0974fb2c88e97066dcea296a7e664a26

oslo_policy/opts.py

@@ -54,13 +54,11 @@ _options = [
                help=_('The relative or absolute path of a file that maps '
                       'roles to permissions for a given service. Relative '
                       'paths must be specified in relation to the '
-                      'configuration file setting this option.'),
-               deprecated_group='DEFAULT'),
+                      'configuration file setting this option.')),
     cfg.StrOpt('policy_default_rule',
                default='default',
                help=_('Default rule. Enforced when a requested rule is not '
-                      'found.'),
-               deprecated_group='DEFAULT'),
+                      'found.')),
     cfg.MultiStrOpt('policy_dirs',
                     default=['policy.d'],
                     help=_('Directories where policy configuration files are '
@@ -69,8 +67,7 @@ _options = [
                            'option, or absolute paths. The file defined by '
                            'policy_file must exist for these directories to '
                            'be searched.  Missing or empty directories are '
-                           'ignored.'),
-                    deprecated_group='DEFAULT'),
+                           'ignored.')),
     cfg.StrOpt('remote_content_type',
                choices=('application/x-www-form-urlencoded',
                         'application/json'),

releasenotes/notes/remove-default-section-fallback-d1485959653438b6.yaml

@@ -0,0 +1,9 @@
+---
+upgrade:
+  - |
+    The following options are no longer loaded from the ``[DEFAULT]`` section.
+    Use the ``[oslo_policy]`` section instead.
+
+    - ``policy_file``
+    - ``policy_default_rule``
+    - ``policy_dirs``