The man who negotiated a deal for Osama bin Laden's extradition to the United States six years ago is daring Senate Democrats to call him as a witness in the upcoming probe into the government's 9-11 intelligence failures, saying he can blow the lid off the Clinton administration's cover-up of the episode. Mansoor Ijaz, a major Clinton financial supporter who hammered out the 1996 bin Laden agreement with the government of Sudan only to have the White House turn the offer down, issued the challenge Thursday during an interview with nationally syndicated radio host Sean Hannity. "I'm saying this point...