get_size doesn't belong to ERP5 API. Use hasData instead

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@35339 20353a03-c40f-0410-a6d1-a30d3c3de9de

product/ERP5OOo/Document/OOoDocument.py

@@ -309,7 +309,7 @@ class OOoDocument(PermanentURLMixIn, BaseConvertableAndFileMixin, File,
     """
     #XXX if document is empty, stop to try to convert.
     #XXX but I don't know what is a appropriate mime-type.(Yusei)
-    if self.get_size() == 0:
+    if not self.hasData():
       return 'text/plain', ''
     # if no conversion asked (format empty)
     # return raw data