pureftpd has a bug where it sends messages like this
```
150-Accepted data connection\r\n
Response code: File status okay; about to open data connection (150)
Response arg: Accepted data connection
150 32768.0 kbytes to download\r\n
150 0.014 seconds (measured here), 1665.27 Mbytes per second\r\n
```
The last `150` is treated as a new response - the previous `150` should have been `150-`.
This means that rclone sees the `150 0.014 seconds (measured here),
1665.27 Mbytes per second` as a reply to the next message and reports
it as an error.
This fix ignores that specific message when it is received in the
`Close` method. It dumps the FTP connection after as it is out of
sync.
See: #3984Fixes#3445
7d70eb0346