LOS ANGELES (Reuters) - Sheryl Crow was diagnosed with a brain tumor last year but she does not worry about it because it is benign, the singer-songwriter told the Las Vegas Review-Journal. In a story posted on the newspaper's website on Tuesday, Crow, whose hits include "All I Wanna Do" and "Soak Up the Sun," said the tumor was discovered when she went to a hospital to be tested because she was experiencing memory loss. "I haven't really talked about it," she told the newspaper's nightclub and entertainment reporter Doug Elfman, "In November, I found out I have a brain tumor. ...