Fix gate: Add feature flag for nova policies removed in Wallaby

This patch set adds a new feature flag called
``removed_nova_policies_wallaby`` under the configuration
group ``[policy-feature-enabled]`` for skipping Nova
tests whose policies were removed in Wallaby. This feature flag
is currently applied to os-agents which is removed in nova
recently - https://review.opendev.org/#/c/749309

Change-Id: Iaa0ddbdca454b93bd8373ce749603f28c5c59180
diff --git a/releasenotes/notes/removed-nova-policies-wallaby-feature-flag-abf3045a0a3e3315.yaml b/releasenotes/notes/removed-nova-policies-wallaby-feature-flag-abf3045a0a3e3315.yaml
new file mode 100644
index 0000000..a72b473
--- /dev/null
+++ b/releasenotes/notes/removed-nova-policies-wallaby-feature-flag-abf3045a0a3e3315.yaml
@@ -0,0 +1,7 @@
+---
+features:
+  - |
+    Added new feature flag called ``removed_nova_policies_wallaby`` under
+    the configuration group ``[policy-feature-enabled]`` for skipping Nova
+    tests whose policies were removed in Wallaby. This feature flag is currently
+    applied to os-agents related policies.