MINOR: stream-int: Remove SI_FL_KILL_CON to rely on conn-stream endpoint only

Instead of setting a stream-interface flag to then set the corresponding
conn-stream endpoint flag, we now only rely the conn-stream endoint. Thus
SI_FL_KILL_CON is replaced by CS_EP_KILL_CONN.

In addition si_must_kill_conn() is replaced by cs_must_kill_conn().
7 files changed