Fix GetNeighborsExecutor empty input result (#549)

* fix GetNeighborsExecutor empty input result

* address comment

Co-authored-by: cpw <13495049+CPWstatic@users.noreply.github.com>

src/executor/query/GetNeighborsExecutor.cpp

@@ -68,8 +68,8 @@ Status GetNeighborsExecutor::buildRequestDataSet() {
 
 folly::Future<Status> GetNeighborsExecutor::getNeighbors() {
     if (reqDs_.rows.empty()) {
-        LOG(INFO) << "Empty input.";
-        DataSet emptyResult;
+        VLOG(1) << "Empty input.";
+        List emptyResult;
         return finish(ResultBuilder()
                           .value(Value(std::move(emptyResult)))
                           .iter(Iterator::Kind::kGetNeighbors)