WASHINGTON, Aug 14 (Reuters) - Moving to quash a political firestorm, the Pentagon on Thursday denied that it will cut the pay of nearly 160,000 U.S. troops in Iraq and Afghanistan by $225 on Sept. 30 when special military pay hikes approved by Congress are due to expire. Defense officials said that even if lawmakers do not reinstate increases passed in April in both "imminent danger pay" and "family separation allowances," the Pentagon will make up the pay losses to troops in those countries in other ways. Undersecretary of Defense David Chu answered sharp criticism from Democratic presidential candidates over...