LOS ANGELES (Reuters) - Whitney Houston's mother has told People magazine that she questions her skills as a parent and wonders if she could have saved her superstar daughter from the drug use that played a role in her death. "Was I a good mother?" Cissy Houston, 79, was quoted as telling the celebrity magazine in an advance excerpt released on Wednesday from the magazine's Friday edition. "I still wonder if I could have saved her somehow. But there's no book written on how to be a parent. You do the best you can. ...