Generate random keystone users

Change-Id: I8dbd07b10d29b43d1c35fa76bcaa0f0efb32beda
Related-Prod: PROD-29868
diff --git a/nova/compute/single.yml b/nova/compute/single.yml
index 2e65d06..287442e 100644
--- a/nova/compute/single.yml
+++ b/nova/compute/single.yml
@@ -31,13 +31,13 @@
         host: ${_param:control_address}
         port: 3306
         name: nova
-        user: nova
+        user: ${_param:mysql_nova_username}
         password: ${_param:mysql_nova_password}
       identity:
         engine: keystone
         host: ${_param:control_address}
         port: 35357
-        user: nova
+        user: ${_param:keystone_nova_username}
         password: ${_param:keystone_nova_password}
         tenant: service
         protocol: ${_param:cluster_internal_protocol}