Chrome / xdg-open torrent client for magnet links

Make Chrome/xdg-open use your BitTorrent client for magnet links  

cd /usr/share/applications

Look for the the .desktop entry for the client you wish to use, ie: deluge.desktop or transmission.desktop

Make sure this entry exists in the .desktop file:
MimeType=application/x-bittorrent;x-scheme-handler/magnet;

Run:
xdg-mime default deluge.desktop x-scheme-handler/magnet