CORD-1250 Update to new Service/Tenancy models

Change-Id: I2e5fa0dd7d62a6451a6726eeaba2c3aaf1b83bc9
diff --git a/xos/volt.xproto b/xos/volt.xproto
index 3145408..e607a23 100644
--- a/xos/volt.xproto
+++ b/xos/volt.xproto
@@ -5,7 +5,7 @@
      option kind = "vOLT";
 }
 
-message VOLTTenant (Tenant){
+message VOLTTenant (ServiceInstance){
      option kind = "vOLT";
      option verbose_name = "vOLT Tenant";