machine_login, but fallback to default DumbHTTPExtractor in case if
   no REMOTE_USER is set
 - use machine_login instead of login, to be synchronised with value
   from extraction plugin


git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@42407 20353a03-c40f-0410-a6d1-a30d3c3de9de