As private as he was in life, so will Joe DiMaggio be in death. His funeral in San Francisco today is expected to be a quiet family affair. Thirty to 40 of his relatives will be allowed to attend the morning funeral mass at Saints Peter and Paul in San Francisco. (The cavernous church actually seats 1,000.) This is the same church where the Yankee Clipper, who died Monday at age 84 after a battle with lung cancer, married his first wife, Dorothy Arnold, in 1939.