LONDON/MELBOURNE (Reuters) - Pressure is building in Britain and Australia for fresh probes into Rupert Murdoch's News Corp, already under siege over phone-hacking claims, after allegations that it ran a secret unit that promoted pirating of pay-TV rivals. The Australian Financial Review on Wednesday alleged that News Corp had used a special unit, Operational Security, set up in the mid-1990s, to sabotage its competitors, reinforcing claims in a BBC Panorama documentary aired earlier this week. ...