Add an optional amphora admin log offloading test

This patch adds an optional amphora admin log offloading scenario
test.

Change-Id: I90e3ed23cdd2aa1125de18dc332c30a9d9cca0a2
diff --git a/octavia_tempest_plugin/config.py b/octavia_tempest_plugin/config.py
index a23f3ae..601c6c8 100644
--- a/octavia_tempest_plugin/config.py
+++ b/octavia_tempest_plugin/config.py
@@ -209,6 +209,10 @@
                default='/var/log/octavia-tenant-traffic.log',
                help='File path, on the tempest system, to the tenant flow '
                     'log file.'),
+    cfg.StrOpt('amphora_admin_log_file',
+               default='/var/log/octavia-amphora.log',
+               help='File path, on the tempest system, to the amphora admin '
+                    'log file.'),
 ]
 
 lb_feature_enabled_group = cfg.OptGroup(name='loadbalancer-feature-enabled',