[ADD] orm.fields_get: include `relation_field` for one2many fields

bzr revid: odo@openerp.com-20111109155645-f7u5z14xhju271d5

openerp/osv/fields.py

@@ -1385,6 +1385,9 @@ def field_to_dict(model, cr, user, field, context=None):
         res['domain'] = field._domain
         res['context'] = field._context
 
+    if isinstance(field, one2many):
+        res['relation_field'] = field._fields_id
+
     return res