Clean out stale data in ring buffer when client disconnects.

src/rtl_tcp.c

@@ -581,6 +581,10 @@ int main(int argc, char **argv)
 
 		printf("all threads dead..\n");
 		
+		// Clear stale data for next client
+		ringbuf_head = ringbuf_tail = 0;
+		memset(ringbuf, 0, ringbuf_sz);
+
 		do_exit = 0;
 	}