Change the call point of lwftp_data_close function

[isjung]

Hello.
Thanks to those who made it.
There was a problem when receiving data, so I am using it after fixing it.
The lwftp_data_close function is terminated in the lwftp_control_process function.
If there is a large amount of data, the termination point is fast and the data connection is terminated before processing the received data.
I use it by modifying it as follows.
lwftp_data_close point is not processed by lwftp_control_process
When data_sink is called, it checks the size and ends it.

[typedef-int-value]

Thank you. referring to your comments, I also fix the download problem.