Add reno and reset legacy policy deprecation expectation

Added a reno to support
https://review.opendev.org/c/openstack/ironic/+/799120
and ultimately removed the "anticipated to be removed in the Xena
development cycle" warnings on legacy policy support as the effort
is taking longer than the cross-team effort anticipated.

Notes added to the code highlight that we need to update the
warnings at that time to ensure we appropriately set expectations
as to when the legacy policies will be removed.

Change-Id: Ie23788abaa61742cdea208fb0cf026bdecaab525

ironic/common/policy.py

@@ -345,10 +345,16 @@ deprecated_bios_disable_cleaning = policy.DeprecatedRule(
     name='baremetal:node:disable_cleaning',
     check_str='rule:baremetal:node:update',
 )
+# TODO(TheJulia): Since the OpenStack community appears to be
+# coalescing around taking a very long term deprecation path,
+# and is actually seeking to suppress the warnings being generated
+# for the time being, I've changed the warning below to remove
+# reference to the Xena cycle. This should be changed once we
+# determine when the old policies will be fully removed.
 deprecated_node_reason = """
 The baremetal node API is now aware of system scope and default roles.
 Capability to fallback to legacy admin project policy configuration
-will be removed in the Xena release of Ironic.
+will be removed in a future release of Ironic.
 """
 
 
@@ -1803,6 +1809,9 @@ def init_enforcer(policy_file=None, rules=None,
     # each policy started filling the logs limit for various tool.
     # Once we move to new defaults only world then we can enable these
     # warning again.
+    # TODO(TheJulia): *When* we go to enable warnings to be indicated
+    # we need to update the notice in the logs to indicate *when* the
+    # support for older policies will be removed.
     _ENFORCER.suppress_default_change_warnings = True
     _ENFORCER.register_defaults(list_policies())
 

releasenotes/notes/silence-rbac-deprecation-for-now-779898e720a7bf4e.yaml

@@ -0,0 +1,10 @@
+---
+other:
+  - |
+    Deprecation warnings for the legacy RBAC policies are now suppressed,
+    as the OpenStack community is coalescing around what appears will be a
+    longer deprecation cycle and process than would typcially be undertaken
+    due to the nature and impact of policy changes. The community as a whole
+    is expecting to make RBAC policy work changes a community goal during the
+    Y* release development cycle, which means the earliest legacy policy
+    support may be removed is likely now the Z* development cycle.