[CORD-1650]
Refactor interface/bridge handling

Change-Id: I83fd9eb3e8440ba277b7b4d1ed41cb18347b6916
diff --git a/roles/interface-config/templates/management.cfg.j2 b/roles/interface-config/templates/management.cfg.j2
index bb3c1e6..de8d942 100644
--- a/roles/interface-config/templates/management.cfg.j2
+++ b/roles/interface-config/templates/management.cfg.j2
@@ -14,6 +14,7 @@
   hwaddress ether {{ ( vtn_net_management_host_hwaddr_prefix ~ ( mgmtbr_ip | ip4_hex )) | hwaddr('unix') }}
   dns-search {{ site_suffix }}
   dns-nameservers {{ dns_servers | join(" ") }}
+  post-down ip link del mgmtbridge
 
 # management bond of physical interfaces
 auto mgmtbond