Fannie Mae’s and Freddie Mac’s safety and soundness regulator this week issued a final rule aimed at beefing up the corporate governance shortcomings that contributed to both government-sponsored enterprises being buffeted by major accounting problems that prompted management shakeups and restated earnings. But the tougher regulations shouldn’t be too much of a burden on Fannie and Freddie as both GSEs individually have already agreed to most of the changes now being sought as part…