When ReportSection list are zero length,
  must remove the mapped frame in a ODF file.

  So that this specification, appending a limitation to
  the ReportSection mapping function. 
  The feature in the FormPrintout accepts only one form 
  in a ReportMethod. 
  You can not set two or more forms in the ReportMethod
  when using FormPrintout.

* Refactoring
  remove unused argument; render_prefix



git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@26403 20353a03-c40f-0410-a6d1-a30d3c3de9de