NEW YORK/WASHINGTON (Reuters) – Six months ago the U.S. oil industry scored a surprise win against farm groups when the Obama administration proposed slashing the amount of ethanol refiners must blend into gasoline, a move that could save them billions of dollars. Stunned by the reversal, producers of the corn-based biofuel and their supporters are now fighting back ahead of a June deadline for the Environmental Protection Agency (EPA) to make a final decision on the cut.