By Lindsay Dunsmuir (Reuters) – U.S. consumer prices were unchanged in July due to a sharp drop in the cost of gasoline, delivering the first notable sign of relief for weary Americans who have watched inflation climb over the past two years. The Consumer Price Index (CPI) was flat last month after advancing 1.3% in June, the Labor Department said on Wednesday in a closely watched report that nevertheless showed underlying inflation pressures remain elevated as the Federal Reserve mulls whether to embrace another super-sized interest rate hike in September. The reading was the largest month-on…