Send goodbye packet before closing stream

Sending it after sending the substream end could incorrectly abort the
substream.

sbotc.c

@@ -776,7 +776,6 @@ static enum stream_state muxrpc_write_sink_1(struct boxs *bs, int infd,
 	if (sz < 0) err(1, "read");
 	if (sz == 0) {
 		ps_write(bs, "true", 4, pkt_type_json, req_id, true, true);
-		ps_goodbye(bs);
 		return stream_state_ended_ok;
 	}
 	ps_write(bs, buf, sz, ptype, req_id, true, false);
@@ -1172,6 +1171,7 @@ do_tcp_connect:
 		if (rc < 0) warnx("tcsetattr");
 	}
 
+	ps_goodbye(&bs);
 	bs_end(&bs);
 	close(s);
 	return rc;