WASHINGTON — The Pentagon is revamping its spy operations to focus on high-priority targets like Iran and China in a reorganization that reflects a shift away from the war zones of Iraq and Afghanistan that have dominated America’s security landscape for the past decade. Under the plan approved last week by Defense Secretary Leon E. Panetta, case officers from the new Defense Clandestine Service would work more closely with counterparts from the Central Intelligence Agency at a time when the military and spy agency are increasingly focused on similar threats. “It will thicken our coverage across the board,” said a...