[CORD-2711]
Use hardcoded fabric MAC address

Change-Id: I4ce29d40dcad030116f06f767c36445b38c7f514
(cherry picked from commit 553f140109fa1a19716162c6eb02a50c0949e1c9)
diff --git a/roles/interface-config/templates/fabric.cfg.j2 b/roles/interface-config/templates/fabric.cfg.j2
index 7c51065..566116b 100644
--- a/roles/interface-config/templates/fabric.cfg.j2
+++ b/roles/interface-config/templates/fabric.cfg.j2
@@ -35,7 +35,7 @@
   network {{ vtn_net_public_cidr | ipaddr('network') }}
   netmask {{ vtn_net_public_cidr | ipaddr('netmask') }}
   broadcast {{ vtn_net_public_cidr | ipaddr('broadcast') }}
-  hwaddress ether {{ ( vtn_net_public_hwaddr_prefix ~ ( vtn_ip | ip4_hex )) | hwaddr('linux') }}
+  hwaddress ether {{ fabric_gateway_hwaddr }}
   post-down ip link del fabricbridge
 
 {% if use_addresspool_vsg %}