NEW YORK — Thunderstorms forced the L.A.-to-Washington flight of Jack Valenti, president and CEO of the Motion Picture Assn. of America, to be diverted Thursday, and put the TV content ratings talks on hold, too.Broadcasters and advocacy groups planned to resume today their attempts to resolve their ongoing dispute over adding content ratings like S for sex to the current age-based ratings. Thursday’s talks were canceled due to Valenti’s absence. Broadcasters got some relief when Sen. John McCain (R.-Ariz.) decided not to schedule a hearing on a bill proposed by Sen. Dan Coats (R.-Ind.) that would penalize TV stations by challenging their licenses at renewal time if their networks did not adopt the letter-code content ratings, which are being pushed by groups like the American Medical Assn., the Parent Teachers Assn. and the Children’s Defense Fund. Broadcasters also got a victory when the Senate passed a spending bill Wednesday that removed a clause that would’ve slapped a spectrum fee of as much as $5 billion on the industry. An earlier House spending bill also includes no spectrum-fee provision.