Fix API audit CADF audit map for failover action

There was a bug in the CADF audit map file for the "failover" action.

This patch corrects the audit map file to handle "failover" correctly
and stop keystonemiddleware from raising an exception.

Change-Id: If3954ba34740e26937dba10bdd8061acde758c88
Story: 2007831
Task: 40116

etc/audit/octavia_api_audit_map.conf.sample

@@ -4,7 +4,7 @@
 target_endpoint_type = load-balancer
 
 [custom_actions]
-failover = failover
+failover = update/failover
 
 # possible end path of API requests
 # path of api requests for CADF target typeURI

releasenotes/notes/fix-audit-map-for-failover-e63390399da6841d.yaml

@@ -0,0 +1,5 @@
+---
+fixes:
+  - |
+    Fixed an issue in the CADF audit map file for failover actions that could
+    cause keystonemiddleware to raise an exception.