Shanna Moakler is auctioning off her engagement ring from Travis Barker. The 47-year-old model was married to the Blink-182 star between 2004 and 2008, and following his recent wedding to Kourtney Kardashian, she’s now decided to auction off her engagement ring. Shanna – who has Landon, 18, and Alabama, 16, with Travis, as well as Atiana, 23, with boxing legend Oscar De La Hoya – told Us Weekly: “I think it is a beautiful piece and truly was my dream ring. “However, that chapter of my life is over and even though wearing it at one time brought me great joy, I hope it will find a new home and c…