At age 68, Cellou Dalein Diallo is running for Guinea's presidential election for the third time. This former technocrat, compromise supporter, once prime minister of former president Lansana ContĂ©, has become one of the biggest opponents of power in place. He hopes, this time, to win the vote against the outgoing head of state, Alpha CondĂ©, whose candidacy for a third term is contested.…