[logging] don't log an error if scheduled reroute is rejected because local node is no longer master

Since it runs in a background thread after a node is added, or submits a cluster state update when a node leaves, it may be that by the time it is executed the local node is no longer master.

src/main/java/org/elasticsearch/cluster/routing/RoutingService.java

@@ -151,9 +151,11 @@ public class RoutingService extends AbstractLifecycleComponent<RoutingService> i
 
                 @Override
                 public void onFailure(String source, Throwable t) {
+                    if (!(t instanceof ClusterService.NoLongerMasterException)) {
                         ClusterState state = clusterService.state();
                         logger.error("unexpected failure during [{}], current state:\n{}", t, source, state.prettyPrint());
                     }
+                }
             });
             routingTableDirty = false;
         } catch (Exception e) {