By Guy Faulconbridge LONDON (Reuters) – The head of Britain’s GCHQ spy service said on Wednesday that new intelligence showed some Russian soldiers in Ukraine had refused to carry out orders, sabotaged their own equipment and accidentally shot down one of their own aircraft. Russia’s Feb. 24 invasion of Ukraine has killed thousands of people, displaced millions and raised fears of a wider confrontation between Russia and the United States. Government Communications Headquarters (GCHQ) chief Jeremy Fleming said President Vladimir Putin had “massively misjudged” the capabilities of Russia’s once…