Fix comment

test/cpp/end2end/grpclb_end2end_test.cc

@@ -1042,7 +1042,7 @@ TEST_F(UpdatesTest, UpdateBalancersDeadUpdate) {
   EXPECT_EQ(0U, backend_servers_[1].service_->request_count());
   WaitForBackend(1);
 
-  // This is serviced by the existing RR policy
+  // This is serviced by the updated RR policy
   backend_servers_[1].service_->ResetCounters();
   gpr_log(GPR_INFO, "========= BEFORE THIRD BATCH ==========");
   CheckRpcSendOk(10);