ATHENS (Reuters) - As Greece's privatization program this month, nearly half a year behind schedule, at stake is not just the billions of euros it needs to raise, but the credibility of its commitment to reforms demanded by its creditors. Greek politicians are under intense pressure at home to resist foreign calls to sell state assets on the cheap and raise fast cash to pay down government debt. More challenging still will be efforts to use privatization as a tool to uproot corrupt business practices and restore foreign investors' confidence in Greece. The 15-month-old Hellenic Republic Asset Development Fund aims to transform dozens of state businesses to increase value before leasing or...