Musician John Mayall, often referred to the “godfather of the British blues,” whose bands of the late ’60s and early ‘70s featured some of the most notable rock instrumentalists of the era, died Monday at home in California, according to a statement posted by his family on his social media accounts. He was 90.Among the fans and organizations posting condolences was the Rock and Roll Hall of Fame, which was set to induct him into its ranks in October.No cause of death was given in the family’s initial statement, although it did refer to Mayall’s recent health setbacks. “It is...