MEDIUM: stream-int: use si_rx_shut_blk() to indicate the SI is closed

Till now we were using si_done_put() upon shutr, but these flags could
be reset upon next activity. Now let's switch to SI_FL_RXBLK_SHUT which
doesn't go away. It's also set in stream_int_update() in case a shutr
condition is detected.

The now unused si_done_put() was removed.
2 files changed