This patch updates the haproxy service scripts to handle the case
where the network interfaces have not yet been plugged. This can
occur in a failover situation.
This patch also makes sure we don't move the management lan interface
into the network namespace.
Closes-Bug: #1509706
Closes-Bug: #1577963
Change-Id: I04d267bd3cdedca11f0350c5255086233cba14ec