LITTLE ROCK, Arkansas (Reuters) – An Arkansas Crime Lab preliminary autopsy confirmed country music singer Mindy McCready's death was a suicide from a single gunshot wound to the head, the Cleburne County Sheriff's Office said on Wednesday. McCready, 37, whose career was overshadowed by substance abuse and suicide attempts, was found dead on the porch of a house in Heber Springs, Arkansas, on Sunday afternoon beside her boyfriend's dead dog. Officials have said she shot the dog. …