Shelley Fabares’ cause of death has been revealed. The actress, who starred in Coach and The Donna Reed Show among other TV series and films, died Saturday after a brief illness. She was 82. Fabares died of pneumonia, her family revealed Thursday to People and other outlets. She had previously been diagnosed with autoimmune hepatitis. And she had a liver transplant in October 2000 after spending nearly two years on the waiting list to receive one. “To her family and friends, Shelley was a source of love, strength, laughter and comfort,” Fabares’ family said in a statement announcing her death. “She was a devoted wife, cherished stepmother,…