Generate random keystone users

Change-Id: I8dbd07b10d29b43d1c35fa76bcaa0f0efb32beda
Related-Prod: PROD-29868
diff --git a/keystone/client/service/octavia.yml b/keystone/client/service/octavia.yml
index c5ca83f..321cf0e 100644
--- a/keystone/client/service/octavia.yml
+++ b/keystone/client/service/octavia.yml
@@ -39,7 +39,7 @@
                 admin_path: '/'
         octavia_identity:
           admin:
-            user: octavia
+            user: ${_param:keystone_octavia_username}
             password: ${_param:keystone_octavia_password}
             project: service
             host: ${_param:keystone_service_host}