Deprecate allow_additional_image_properties

Change-Id: I1c602e3817e0e89a6f7ebbf79adc1156d0b8a1aa
Implements: bp deprecate-allow-custom-props

glance/common/config.py

@@ -171,6 +171,13 @@ _DEPRECATE_GLANCE_V1_MSG = _('The Images (Glance) version 1 API has been '
 
 common_opts = [
     cfg.BoolOpt('allow_additional_image_properties', default=True,
+                deprecated_for_removal=True,
+                deprecated_since="Ussuri",
+                deprecated_reason=_("""
+This option is redundant.  Control custom image property usage via the
+'image_property_quota' configuration option.  This option is scheduled
+to be removed during the Victoria development cycle.
+"""),
                 help=_("""
 Allow users to add additional/custom properties to images.
 

releasenotes/notes/deprecate-allow_additional_image_props-0e3b2f1ffa4e55e1.yaml

@@ -0,0 +1,14 @@
+---
+deprecations:
+  - |
+    The Glance API configuration option ``allow_additional_image_properties``
+    is deprecated in this release and is subject to removal at the beginning
+    of the Victoria development cycle, following the `OpenStack standard
+    deprecation policy
+    <https://governance.openstack.org/reference/tags/assert_follows-standard-deprecation.html>`_.
+
+    The migration path for operators who were using this option in its
+    nondefault ``False`` setting is to set the ``image_property_quota``
+    option to ``0``.  Since many other OpenStack services depend upon the
+    ability to read/write custom image properties, however, we suspect that
+    no one has been using the option with a nondefault value.