COLOMBO, Sri Lanka (AP) — In a stunning election result that was unthinkable just weeks ago, Sri Lanka’s longtime president acknowledged Friday that he had been defeated by a onetime political ally, signaling the fall of a family dynasty and the rise of former Cabinet minister Maithripala Sirisena. Sirisena, who defected from the ruling party in a surprise move in November, capitalized on the outgoing President Mahinda Rajapaksa’s unpopularity among this island’s ethnic and religious minorities, as well as grumbling among the Sinhalese majority about his growing power and the country’s economic troubles.