ADEN/DUBAI, Sept 12 - Saudi Arabia has shut down its East-West pipeline after the vital oil conduit came under aerial attack in the widening Middle East war. The world’s largest crude oil exporter temporarily closed the pipeline after a drone attack that both Baghdad and Riyadh said had originated in Iraq, where Iranian-backed militias operate. Iraq dismissed a military commander on Saturday in response to the attack. The 1,200-kilometre (745-mile) pipeline running across the Arabian Peninsula had helped Saudi Arabia to bypass a shipping logjam in the Strait of Hormuz, where tanker traffic has slowed to a trickle due to...