fix(db): fix compile error

Former-commit-id: b0734cdc673bbc74ef8b670e2d6f56edc5364eec

cpp/src/db/LocalMetaImpl.cpp

@@ -15,7 +15,7 @@ namespace vecwise {
 namespace engine {
 namespace meta {
 
-long GetFileSize(const std::string& filename)
+long LocalMetaImpl::GetFileSize(const std::string& filename)
 {
     struct stat stat_buf;
     int rc = stat(filename.c_str(), &stat_buf);

cpp/src/db/LocalMetaImpl.h

@@ -53,6 +53,7 @@ private:
     std::string GetGroupMetaPath(const std::string& group_id);
 
     Status CreateGroupMeta(const GroupSchema& group_schema);
+    long GetFileSize(const std::string& filename);
 
     Status initialize();