Most FTP servers do not support the ABOR command (they don't process
control channel traffic until the data channel is finished). Or they
require the telnet IP & sync procedure on the control channel (this
requires sending TCP urgent data, which we do not support).
Following behaviour of most browsers and GUI FTP clients, abort
downloads by resetting the data channel.
Abort of uploads needs no change, because the client closes the data
channel rather than the server.
Task-number: QTBUG-25494
Change-Id: I69e7b7c04d709d26def9a4a7081074e1cbf69701
Reviewed-by: Martin Petersson <Martin.Petersson@nokia.com>
a5fcd3f799