Magical Mystery Tour through VMap, vaddrs.conf.

CLEANUP: Virtual IPs were once managed such that within a cluster they
       would automatically rebalance themselves between nodes by bringing
       subinterfaces up and down. After ATS was open sourced the original
       setuid tool, vip_config (or traffic_vip_config) was inadvertently
       removed; but the code which depended on this tool was not cleaned
       up.

       Since modern deployments either do not use this tool at all
       (because it was broken for a few years) and modern deployments also
       have some central system for managing cluster state reliably, we
       do not need VMap to implement some scheme for automatically
       rebalancing the ips.

       This CL keeps much of the code for detecting ip address conflicts
       and for receiving the multicast messages from the cluster; but we
       remove all instances where we either bring up/down an interface.

       Deployments should manage this through external state systems.

       Note: VIPs do not actually bind to the specific addresses in
       vaddrs; this is just an operations convience to ensure that a
       cluster has no ip conflicts or unmanaged vips.

       Note: The *right* thing to do here may be to recall that old tool and let
       VMap do it's thing.

       Note: Another *right* thing to do may be to remove VMap entirely, along
       with the associated cluster messages. At least with this exiting changeset
       we can detect ip address conflicts.

Reviewed-by: TBD