Dogged by weeks of questions about whether her claims of Native American heritage helped advance her career, Elizabeth Warren now faces skepticism from some of Boston’s black ministers whose appearance with Scott Brown just after his 2010 election to US Senate helped shape Brown’s image as a different breed of Republican. “It will take more than an impromptu endorsement by Governor Patrick to make an intellectually compelling case why Elizabeth Warren deserves to be the next senator,” said the Rev. Eugene F. Rivers III, referring to the state’s governor, Deval Patrick, who is black. Rivers said he will ask Warren...