Add more verbose error indicator for scenario

engine-core/src/main/java/io/nosqlbench/engine/core/script/Scenario.java

@@ -263,6 +263,7 @@ public class Scenario implements Callable<ScenarioResult> {
                 System.out.flush();
             } catch (Exception e) {
                 this.state = State.Errored;
+                logger.warn("Error in scenario, shutting down.");
                 this.scenarioController.forceStopScenario(5000, false);
                 throw new RuntimeException(e);
             } finally {