Method dec_opened_inodes

src/client/Client.h:1012–1014

    ++opened_inodes;
  }
  void dec_opened_inodes() {
    --opened_inodes;
  }
  std::pair<uint64_t, uint64_t> get_opened_inodes_rates() {
    return std::make_pair(opened_inodes, inode_map.size());
  }