UNITED NATIONS (Reuters) - The U.N.-established panel that investigated the Iraq oil-for-food program will stay open until the end of the year to allow prosecutors access to its documents, the United Nations said on Friday. Investigators and prosecutors from 28 countries have already requested documents from the Independent Inquiry Committee since it released its final report on October 27, said Michael Holtzman, spokesman for the IIC, whose Manhattan office has been reduced to a skeletal staff. The IIC had been scheduled to close at the end of this month. The panel, headed by former U.S. Federal Reserve Chairman Paul Volcker,...