w_scan leaves out all channels with horizontal polarisation in some setups

[cucujoidea]

with a Technisat SkyStar2 DVB card, w_scan in a tested setup leaves out all horizontal polarized channels. This bug also appears in some other programs, it was analyzed and fixed for kaffeine: https://bugs.kde.org/show_bug.cgi?id=374693 . It appears that this card (Technisat SkyStar2) supports to set a higher LNBf voltage, which is required sometimes. This bug does not appear in vlc, so starting vlc with a valid channel list, quitting it again, and then starting w_scan (or another program) makes w_scan work since then the setting is correct until the next reboot. If there was a similar option directly in w_scan, it would make such setups work.