By Blake Brittain (Reuters) -A U.S. appeals court on Thursday revived a lawsuit accusing the rock band Nirvana of publishing child pornography by using a photograph of a naked four-month-old baby on the cover of its hit 1991 album “Nevermind.” The 9th U.S. Circuit Court of Appeals overturned a lower court’s decision that Spencer Elden, the baby depicted on the cover, had waited too long to bring his lawsuit against the seminal Seattle grunge band. The court did not address whether the cover of “Nevermind” constitutes child pornography. “This procedural setback does not change our view,” Nirvan…