A historic Los Angeles hospital that has been a popular location for filming movies and television shows will soon become affordable housing for low-income seniors. Two decades after shutting its doors, the old Linda Vista Community Hospital is about to get a $40 million transformation and a new purpose. Work is expected to start in about two weeks to convert the former nurses’ residence into 23 seniors apartments. A second phase calls for transforming the main hospital building into 74 apartments. Although it has been closed since 1991, the mission revival-style complex has been a popular filming location. It has been used in numerous movies, including “Pearl Harbor,” “Outbreak,” and “Se7en.” Television shows, including “Buffy the Vampire Slayer,” the pilot episode of “ER,” and, more recently, “True Blood” have also filmed on site.