NEW YORK (Reuters) – As a war of nerves between U.S. shale producers and Gulf powerhouses intensifies, OPEC’s biggest members are counting down the months until their upstart rivals lose the one thing shielding them from crashing oil prices – hedges. They may need much more patience than they reckon, however, because those hedges are a moving target. Rather than wait for their price insurance to run out, many companies are racing to revamp their policies, cashing in well-placed hedges to increase the number of future barrels hedged, according to industry consultants, bankers and analysts familiar with the deals. OPEC officials hope that once U.S. oil companies get fully exposed to the impact of an over 50 percent slide in crude prices since last June, they will have to drill fewer new wells, causing U.S. production growth to stall and putting a floor under oil prices now testing $50 […]