By John O’Donnell and Huw Jones FRANKFURT/LONDON (Reuters) – The European Central Bank is preparing banks for a possible Russian-sponsored cyber attack as tensions with Ukraine mount, two people with knowledge of the matter said, as the region braces for the financial fallout of any conflict. The stand-off between Russia and Ukraine has rattled Europe’s political and business leaders, who fear an invasion that would inflict damage on the entire region. Earlier this week, French President Emmanuel Macron shuttled from Moscow to Kyiv in a bid to act as a mediator after Russia massed troops near …