forgets ssl for splitted archives in ftp sources with auth ssl/tls

[Rhino-Cracker]

IN SHORT:
Source = ftp://un:pw@my.dyndns.org:1337/Videos/|auth=TLS&verifypeer=false
download of vid.rar is encrypted < correct
download of vid.r00 is not encrypted < erronous, should be encrypted
download of vid.r01 is not encrypted < erronous, should be encrypted

In detail:
Hi all,
I spent a few hours and the patience of a XBian dev to trace down this error until a point where I think someone knowing the code might be much faster than me in finding the actual line and fixing it. :)

When using a FTP Source with Auth SSL/TLS, that has splitted (uncompressed) RAR-Archives in it, the plugin seems to forget that the FTP needs an encrypted connection to download the splitted parts. It startes loading the .rar file using the encrypted connection.
But somewhere in the iteration over the parts (.r00, .r01, ...), it looses this information and tries to download the parts through an unencrypted connection.
The FTP Server, enforcing the use of an encrypted connection, refuses the connection attempt, which results in a few connection timeouts/aborts.

An example source path to clearify what I mean and what I've tested: ftp://un:pw@my.dyndns.org:1337/Videos/|auth=TLS&verifypeer=false .

How to reproduce:

1. Use any FTP Server that is capable to use and enforce Auth SSL/TLS login/command channel, secure listing and secure file transfer. I used Gene6. Configure an account so it has to encrypt command+data+listing channels.
2. Place a kodi compatible mkv file in a splitted RAR-Archive (no compression = save only, old filename format (vid.r01 instead of vid.part1.rar)) on that server.
3. Add the FTP Server as a source in kodi and try to play back that splitted video. See the debug log and the FTP Server log how it refuses the unencrypted connections for r00, r01, ...
4. Optional: Unpack the RAR on the FTP Server machine and see that playback of the unarchived video works through the encrypted data channel.

This issue might be related to:
#100 Playback dont work in combination with FTPS