It seemed like Julie Felss Masino had saved her job as chief executive officer of Cracker Barrel Old Country Store Inc. After a logo change ensnared the restaurant chain in the culture wars, Masino had the company back on track. The stock has more than doubled year-to-date, making Cracker Barrel the S&P Composite 1500 Restaurants Index’s best performer. In June, the company reported a surprise profit for the quarter and raised its forecasts for the year. One month later, Masino is out. The decision sent the shares down more than 2 percent and left some analysts scratching their heads. But women who have sat in the corner office know better. Boards are moving much faster to fire the big boss when things go bad, based on the past few years of CEO turnover rates. The phenomenon is even more acute for female CEOs, who have always been under more intense scrutiny than their male counterparts. Over the past decade, women CEOs of Russell 3000 companies left after an average tenure of 6.2 years versus 8.9 years for men, according to Exechange, which tracks executive changes. In examining the r