fix #6369, Consumer cant set correct retries via generic invocation (#6370)

Author: shadowmind

dubbo-cluster/src/main/java/com/alibaba/dubbo/rpc/cluster/support/FailoverClusterInvoker.java

@@ -28,6 +28,7 @@
 import com.alibaba.dubbo.rpc.RpcException;
 import com.alibaba.dubbo.rpc.cluster.Directory;
 import com.alibaba.dubbo.rpc.cluster.LoadBalance;
+import com.alibaba.dubbo.rpc.support.RpcUtils;
 
 import java.util.ArrayList;
 import java.util.HashSet;
@@ -54,7 +55,8 @@ public FailoverClusterInvoker(Directory<T> directory) {
     public Result doInvoke(Invocation invocation, final List<Invoker<T>> invokers, LoadBalance loadbalance) throws RpcException {
         List<Invoker<T>> copyinvokers = invokers;
         checkInvokers(copyinvokers, invocation);
-        int len = getUrl().getMethodParameter(invocation.getMethodName(), Constants.RETRIES_KEY, Constants.DEFAULT_RETRIES) + 1;
+        String methodName = RpcUtils.getMethodName(invocation);
+        int len = getUrl().getMethodParameter(methodName, Constants.RETRIES_KEY, Constants.DEFAULT_RETRIES) + 1;
         if (len <= 0) {
             len = 1;
         }