Manhattan district-attorney candidate Cyrus Vance Jr. canceled a fund-raiser scheduled for today because he feared a madam might show up and ask some tough questions. The madam, Kristen Davis, announced she would protest outside the event because it was to be held at the home of Eliot Spitzer, the former governor to whom she says she supplied prostitutes. Later Davis served four months in jail for promoting prostitution, and Spitzer wasn’t even charged for any of his involvement in the activity. “Cy decided that what was supposed to be a small get-together had grown into something that was beginning to overshadow the important issues in this race,” a spokesman explained. Dude, if you can’t stand up to one hooker, how on earth are you going to handle being the D.A. for Manhattan?