By Can Sezer, Rowena Edwards and Julia Payne ISTANBUL/LONDON, Feb 6 (Reuters) - A massive earthquake that struck Turkey and Syria on Monday halted operations at Turkey's major oil export hub in Ceyhan and stopped key crude oil flows from Iraq and Azerbaijan, officials said. The Tribeca shipping agency said in a notice that the BTC terminal at Ceyhan that exports Azeri crude oil will be closed through...