Hollywood union leaders warned of the possibility of another strike this summer if the studios cannot reach a deal before crew contracts expire on July 31. Speaking to a rally of more than 2,000 crew members on Sunday at Woodley Park in Encino, Sean O’Brien, the president of the International Brotherhood of the Teamsters, said the unions should commit to withhold their labor — and not grant an extension — if a deal is not agreed by the deadline. “We are not afraid to strike,” O’Brien said. “If these greedy corporations — whether it’s Amazon, Netflix, Sony… Disney — if...