RSVP Base PSB/RSB key

[tsaad-dev]

   |     +--ro psbs
   |     |  +--ro psb* []
   |     |     +--ro source-port?   inet:port-number
   |     |     +--ro expires-in?    uint32
   |     +--ro rsbs
   |        +--ro rsb* []
   |           +--ro source-port?         inet:port-number
   |           +--ro reservation-style?   identityref
   |           +--ro expires-in?          uint32

Make source-port key.