fix compile error

Author: liuyu85cn

src/storage/GraphStorageServiceHandler.h

@@ -60,9 +60,6 @@ class GraphStorageServiceHandler final : public cpp2::GraphStorageServiceSvIf {
   folly::Future<cpp2::ExecResponse> future_chainDeleteEdges(
       const cpp2::DeleteEdgesRequest& req) override;
 
-  folly::Future<cpp2::ScanVertexResponse> future_scanVertex(
-      const cpp2::ScanVertexRequest& req) override;
-
   folly::Future<cpp2::ScanResponse> future_scanEdge(const cpp2::ScanEdgeRequest& req) override;
 
   folly::Future<cpp2::GetUUIDResp> future_getUUID(const cpp2::GetUUIDReq& req) override;