Fix issue with FTP server not detecting silent close by client.
Fix issue with FTP server not detecting silent close by client.

Actually detect receiving zero bytes from client ... the while()
loop only checks for values <> 0.

Found playing around with Python ftplib when fixing issue #2.

Signed-off-by: Joachim Nilsson <583c295fd7602c168ad814279bbc3894ba65f5d6@gmail.com>

troglobit/uftpd,troglobit/uftpd