HAVANA — Rock legends the Rolling Stones strutted and sang before hundreds of thousands of jubilant Cubans in Havana on Friday, delivering a historic concert in a country that once forced fans to listen to their favorite music behind closed doors. “Hello Havana! Good evening to my Cuban people,” lead singer Mick Jagger shouted in excellent Spanish as he launched into the band’s classic “Jumpin’ Jack Flash.” Coming two days after Barack Obama finished the first trip to Cuba by a U.S.