The Nashville high school where a teen gunman killed a fellow student last week had no metal detectors — apparently because administrators think they could be racist.A former board member told The Post that the misguided administrators are responsible for keeping them out even over many parents’ objections. “I knew this day was gonna happen,” said Fran Bush, formerly a Metro Nashville Public Schools board member. Bush, who served on the MNPS board from 2018 to 2022, said she pushed for metal detectors throughout her tenure but that district Director Adrienne Battle “didn’t want to hear it” — even as...