Update iptorrents.py

Adds another URL parameter when searching on iptorrents for brrip.  This allows it to find brrip that are also classified as 720p/1080p.

See this thread for info:
https://couchpota.to/forum/viewtopic.php?f=5&t=4032&sid=7892abbaaca9dad8bd3cc27cafb7fd33

And this prior pull request for more info:
https://github.com/RuudBurger/CouchPotatoServer/pull/3696

I just tested this out and it works exactly as expected, giving the following URL:
https://www.iptorrents.com/torrents/?l7=&l48=&q=%22kung+fu+panda+2%22+2011&qf=ti&p=1