fix: apply_discount_on field should be of type Select not Data

erpnext/accounts/doctype/subscriptions/subscriptions.json

@@ -462,7 +462,7 @@
    "collapsible": 0, 
    "columns": 0, 
    "fieldname": "apply_additional_discount", 
-   "fieldtype": "Data", 
+   "fieldtype": "Select", 
    "hidden": 0, 
    "ignore_user_permissions": 0, 
    "ignore_xss_filter": 0, 
@@ -656,7 +656,7 @@
  "issingle": 0, 
  "istable": 0, 
  "max_attachments": 0, 
- "modified": "2018-03-01 08:24:07.659772", 
+ "modified": "2018-03-01 17:12:11.105074", 
  "modified_by": "Administrator", 
  "module": "Accounts", 
  "name": "Subscriptions",