added default date to planned start date in Prod Order & made planned end date read-only

erpnext/manufacturing/doctype/production_order/production_order.json

@@ -167,7 +167,7 @@
    "read_only": 0
   }, 
   {
-   "default": "", 
+   "default": "now", 
    "fieldname": "planned_start_date", 
    "fieldtype": "Datetime", 
    "label": "Planned Start Date", 
@@ -179,8 +179,10 @@
    "fieldname": "planned_end_date", 
    "fieldtype": "Datetime", 
    "label": "Planned End Date", 
+   "no_copy": 1, 
    "permlevel": 0, 
-   "precision": ""
+   "precision": "", 
+   "read_only": 1
   }, 
   {
    "fieldname": "column_break_13", 
@@ -356,7 +358,7 @@
  "idx": 1, 
  "in_create": 0, 
  "is_submittable": 1, 
- "modified": "2015-04-01 07:32:38.426624", 
+ "modified": "2015-04-13 02:44:17.319988", 
  "modified_by": "Administrator", 
  "module": "Manufacturing", 
  "name": "Production Order",