Fix type route_result() in linc_us5_routing

The second element is a flow_id(), not an integer().
Use proper packet-in reasons

The 1.4 spec introduced new packet-in reasons.  Ensure that we use the
correct reason throughout.  Also handle the new values when determining
how much of the packet to send to the controller.

This is part of FlowForwarding/LINC-Switch#262.