Breakout ports are identified with a ':\d+' suffix in their port
description. This extension of the existing hack for submodules lets
breakout ports be referenced by their ifindex instead of trying to
encode the combination of module, submodule, port, and subport into a
single port number in the database.  This is total crap, and makes me
hate the mod/port DB encoding we have even more.  It is on my TODO list
to move snmpit to using device-specific port identification based on
port description strings instead.

NOTE: The module number semantics have changed for the submod/subport
hack.  Instead of using whatever module the port is on (plus one...),
the module is set to '0'. This is what should be used in the 'wires' DB
table.