TCP profile: improve traces in tcp_decide_SO_packet()
TCP profile: improve traces in tcp_decide_SO_packet()

* a debug trace should have been a warning trace.
* add a debug trace printing the selected packet type at the very end of the
  function.

didier-barvaux/rohc,didier-barvaux/rohc,didier-barvaux/rohc,didier-barvaux/rohc,didier-barvaux/rohc