(channel_adjust_rec_window): Check that written > 0.

Rev: src/channel.c:1.125.2.12

src/channel.c

@@ -268,7 +268,7 @@ channel_adjust_rec_window(struct ssh_channel *channel, uint32_t written)
 {
   /* NOTE: The channel object (referenced as a flow-control callback)
    * may live longer than the actual channel. */
-  if (! (channel->flags & (CHANNEL_RECEIVED_EOF | CHANNEL_RECEIVED_CLOSE
+  if (written && ! (channel->flags & (CHANNEL_RECEIVED_EOF | CHANNEL_RECEIVED_CLOSE
 				      | CHANNEL_SENT_CLOSE)))
     SSH_CONNECTION_WRITE(channel->connection, prepare_window_adjust(channel, written));
 }