remove duplicated definition.

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@30418 20353a03-c40f-0410-a6d1-a30d3c3de9de

product/ERP5Type/Base.py

@@ -3187,9 +3187,6 @@ class Base( CopyContainer,
   def Description(self):
     return self.getDescription('')
 
-  def Contributors(self):
-    return self.getContributorList('')
-
   def EffectiveDate(self):
     return self.getEffectiveDate('None')