optimize the RondRobinLoadBalance and MockClusterInvoker (#2932)

delete unused logic and take the logger out.

Author: lixiaojiee

dubbo-cluster/src/main/java/org/apache/dubbo/rpc/cluster/loadbalance/RoundRobinLoadBalance.java

@@ -108,7 +108,6 @@ protected <T> Invoker<T> doSelect(List<Invoker<T>> invokers, URL url, Invocation
                 weightedRoundRobin = new WeightedRoundRobin();
                 weightedRoundRobin.setWeight(weight);
                 map.putIfAbsent(identifyString, weightedRoundRobin);
-                weightedRoundRobin = map.get(identifyString);
             }
             if (weight != weightedRoundRobin.getWeight()) {
                 //weight changed

dubbo-cluster/src/main/java/org/apache/dubbo/rpc/cluster/support/wrapper/MockClusterInvoker.java

@@ -86,12 +86,12 @@ public Result invoke(Invocation invocation) throws RpcException {
             } catch (RpcException e) {
                 if (e.isBiz()) {
                     throw e;
-                } else {
-                    if (logger.isWarnEnabled()) {
-                        logger.warn("fail-mock: " + invocation.getMethodName() + " fail-mock enabled , url : " + directory.getUrl(), e);
-                    }
-                    result = doMockInvoke(invocation, e);
                 }
+                
+                if (logger.isWarnEnabled()) {
+                    logger.warn("fail-mock: " + invocation.getMethodName() + " fail-mock enabled , url : " + directory.getUrl(), e);
+                }
+                result = doMockInvoke(invocation, e);
             }
         }
         return result;