The original lineup ofheavy metal legends Black Sabbath, according to multiple industry sources, was scheduled to headline Coachella this year, but was forced to back out just days ago when guitarist Tony Iommi was diagnosed with lymphoma, a type of cancer.  The lineup was announced Monday, just days after Iommi's diagnosis, leaving festival organizers just days to decide who to bump up o headliner.  Radiohead, the Black Keys, and rappers Snoop Dogg and Dr. Dre were announced as headliners, theough it is not clear which act replaced Sabbath.