It’s back to the future for San Diego Civic Light Opera, producer of the Starlight musicals.To replace Bud Franks, who recently resigned as executive producer and general manager, the SDCLO board turned to Leon Drew, who retired from those posts in 1988. Drew, 73, said he considers himself an interim choice. He’ll seek to get the 46-year-old organization back on its regular profitable path. It has struggled for several seasons after decades of success. Last summer’s season lost money, and the company this fall had start-up costs for its first indoor series, contributing to a deficit Franks said could reach $ 500,000 by Dec. 31.