When one of New York's top political leaders, Herman D. Farrell Jr., questioned having a party in South Boston during the Democratic National Convention this summer, saying that neighborhood had a "history of racial turmoil and tension," a Boston official called him a "racial agitator" and insisted that the busing fight of the 1970's had little to do with racism. Mr. Farrell, the longtime assemblyman from Manhattan who also is chairman of the state party, immediately tried to reduce the chance of a racial flare-up, saying yesterday that he was satisfied that Boston had changed since 1974, when some white...