SANGMI CHA and HYONHEE SHIN SOUTH Korea's call for a formal end to the Korean War is premature but the door for dialogue is open if it scraps its double standards and hostile policy, a senior North Korean official said in comments published by state media on Friday. The 1950-53 Korean War ended with an armistice not a peace treaty, leaving U.S.-led U.N. forces technically still at war with North Korea. The question of formally ending the war has become caught up in a U.S.-led effort to get North Korea to give up it nuclear weapons. South Korea President Moon…