Two police officers have been sentenced to seven years in prison for beating to death a Shiite opposition activist in custody during last year’s crackdown on protesters. The sentences, reported Sunday by the state news agency BNA, were criticized as too lenient by critics and may do little to blunt international criticism of human rights abuses since Bahrain’s Sunni Muslim rulers quelled a Shiite-led uprising last year. The activist, Kareem Fakhrawi, a businessman and a member of Wefaq, the leading opposition group in Bahrain, died in custody in April 2011, a week after he went to a police station to complain about his house being demolished by the police, opposition members said. “The prosecutor changed the charges from ‘torture leading to death’ to ‘beating leading to death,’ ” said Sayed Hadi al-Mousawi, a member of Wefaq. “They don’t want to admit that there was torture.”