[MEDIUM] process_srv_data: ensure that we always correctly re-arm timeouts

We really want to ensure that we don't miss a timeout update and do not
update them for nothing. So the code takes care of updating the timeout
in the two following circumstances :
  - it was not set
  - some I/O has been performed

Maybe we'll be able to remove that from stream_sock_{read|write}, or
we'll find a way to ensure that we never have to re-enable this.
1 file changed