By Vera Eckert and Tom Käckenhoff FRANKFURT (Reuters) – Germany, the world’s fourth-biggest economy, is preparing for all scenarios including a complete stop to Russian gas supplies once a regular 10-day maintenance period on the giant Nord Stream 1 pipeline ends. Maintenance on the pipeline, which carries Russian gas directly into Germany, began on July 11 but Berlin is factoring in gas being used by the Kremlin to exert political pressure on the West, something denied by Moscow. Here are some of the risks should the outage period last longer or the pipeline reopen with reduced flows. WHY IS …