[wishlist] Make tracker exchange feature (lt_trackers) switchable

Ok, that's an easy-fix.

one more topic about this http://qbforums.shiki.hu/viewtopic.php?f=15&t=189

2.8.0 beta4 nothing changed

I've made patch which fix this issue for qbittorrent-2.7.3
It adds checkbox for GUI (BitTorrent tab in preferences) and for webUI.

Please review it :)

@lamskoy: This is not the correct way to fix this. Here is why I think so:
1. This should be in advanced preferences not in regular ones.
2. Why only the tracker extension? users will wonder why they can disable the lt_tracker extension but not the other ones (qBittorrent supports a few others). Thus, a simple checkbox does not do the trick.
3. From a programming point of view, your patch is fine although I don't think it should be called LT (since LT means LibTorrent and the extension is called lt_trackers).

I will file a bug report against libtorrent itself. I believe the the best fix there is to disable this extension ONLY for private torrents. Similarly, DHT is already disabled for such torrents.

libtorrent v0.15.6 is likely to stop sharing private trackers with other peers. I also fixed qBittorrent so that it completly disables the lt_trackers extension if libtorrent <= 0.15.5 is detected because of this security issue.

v2.8.0 is going to be released withing 2 weeks (release candidate tomorrow).

According to the libtorrent author, libtorrent is NOT sharing trackers for torrents that are private.
Has anyone of you actually experienced the problem and did you just assume it was unsafe?

If you really experience this problem with private torrents then this likely means that the torrent was not indicated as being private when created. In that case, the problem comes from the torrent creator. If the private flag is not set for such torrents, DHT is also be used (so tracker exchange is the least of your problems).

Many private trackers allow DHT, it does not affect the correct account of the rating and safety of passkey (But not when using some clients that are prohibited on these trackers, for example: BitComet and Azureus for rutracker.org).
In other words, the privacy of the torrent is not related to the private tracker. And if the torrent was not indicated as being private when created that does not mean that it created specifically for open tracker.