Write policy.json on leader-settings-changed

Commit 855c954c30 revealed a bug
that occurrs some times when having multpile Keystone units.

Change-Id: I7bfce6db6b0dba855af32aef4c3f496f03a5a34b
Related-Bug: #1637453

hooks/keystone_hooks.py

@@ -480,6 +480,9 @@ def leader_settings_changed():
     # sure only the leader is running the cron job.
     CONFIGS.write(TOKEN_FLUSH_CRON_FILE)
 
+    # Make sure we keep domain and/or project ids used in templates up to date
+    CONFIGS.write(POLICY_JSON)
+
     update_all_identity_relation_units()
 
 

unit_tests/test_keystone_hooks.py

@@ -455,7 +455,11 @@ class KeystoneRelationTests(CharmTestCase):
         self.relation_ids.return_value = ['identity:1']
         self.related_units.return_value = ['keystone/1']
         hooks.leader_settings_changed()
-        mock_write.assert_has_calls([call(utils.TOKEN_FLUSH_CRON_FILE)])
+        mock_write.assert_has_calls(
+            [
+                call(utils.TOKEN_FLUSH_CRON_FILE),
+                call(utils.POLICY_JSON),
+            ])
         self.assertTrue(update.called)
 
     def test_ha_joined(self):