A judge ruled Friday that charges against George Shirakawa Jr. for his alleged involvement in a 2010 political mail fraud scandal should not be thrown out as part of a plea deal the disgraced former county supervisor agreed to earlier this year. The ruling was a victory for prosecutors, whose efforts to put Shirakawa behind bars had stalled in recent months. “We think justice was done,” said prosecutor Karyn Sinunu-Towery. “It was fair.”