Industry observers believe the White House is making a significant move to upgrade oversight of the Federal Home Loan Bank System by nominating the current president of Ginnie Mae to fill a vacant slot on the five-member Federal Housing Finance Board. President Bush announced last week that he intends to nominate Ronald Rosenfeld to serve out the remainder of a seven-year term on the FHFB that was recently vacated by John Korsmo, who resigned from the…