Commit 1af862791ef83d2d67d71a4db6d37b919accb3d5 broke us.
A general run of thumb is that in most cases when tests rely on
IP's/MAC's we should set the enable_dhcp=False. The reason for this
is that the upstream code does not have the DHCP port automatically
allocated.
Change-Id: Ibc762b17e256faa03c00eeeab75aefaa16e08592