Add support for specialise category in order to refer to Trade Condition from any Ticket if needed

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@27137 20353a03-c40f-0410-a6d1-a30d3c3de9de

product/ERP5/PropertySheet/Ticket.py

@@ -38,4 +38,4 @@ class Ticket:
       'mode'        : 'w' },
   )
 
-  _categories = ()
+  _categories = ('specialise', )