Log Message:
lftp: updated to 4.8.4

Version 4.8.4:
* fixed a security vulnerability with "file:" file names.
* fixed mirror --flat.
* http: extract links from <source> tags.
* fixed upload of zero-length files over ftps.
* fixed assert on "mput -d".
* fixed a core dump.
* avoid multiple backup files of DHT cache.
* translations updated (uk, zh_CN).