Groom’s accident, Merv Griffin’s death lend gloomy air to Lava Man’s barn

These are rueful times in the barn of Lava Man, the richest claiming horse in thoroughbred history. The horse’s groom lost his left arm in a freeway accident July 23. Then Merv Griffin, who was trainer Doug O’Neill’s highest-profile client, died last Sunday of prostate cancer. A pall has settled over O’Neill’s operation leading to the $1 million Pacific Classic at Del Mar on Sunday when Lava Man…