# File rbot/registry.rb, line 44
    def upgrade_data
      if File.exist?("#{@bot.botclass}/registry.db")
        puts "upgrading old-style (rbot 0.9.5 or earlier) plugin registry to new format"
        old = BDB::Hash.open "#{@bot.botclass}/registry.db", nil, 
                             "r+", 0600, "set_pagesize" => 1024,
                             "set_cachesize" => [0, 32 * 1024, 0]
        new = BDB::CIBtree.open "#{@bot.botclass}/plugin_registry.db", nil, 
                                BDB::CREATE | BDB::EXCL | BDB::TRUNCATE,
                                0600, "set_pagesize" => 1024,
                                "set_cachesize" => [0, 32 * 1024, 0]
        old.each {|k,v|
          new[k] = v
        }
        old.close
        new.close
        File.delete("#{@bot.botclass}/registry.db")
      end
    end