revert my 41477: a better patch by Nicolas (the first ;) is awaiting review

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@41485 20353a03-c40f-0410-a6d1-a30d3c3de9de

product/ERP5/Tool/ContributionTool.py

@@ -203,14 +203,8 @@ class ContributionTool(BaseTool):
 
     if portal_type is None:
       # Guess it with help of portal_contribution_registry
-
-      # XXX may be broken for non-cStringIO files / IO that cant be replayed?
-      data = file_object.read()
-      file_object.seek(0)
-
       registry = portal.portal_contribution_registry
       portal_type = registry.findPortalTypeName(filename=filename,
-                                                data=data,
                                                 content_type=content_type)
     #
     # Check if same file is already exists. if it exists, then update it.