Removed update_job_card_reference method (#15614)

diff --git a/erpnext/manufacturing/doctype/job_card/job_card.py b/erpnext/manufacturing/doctype/job_card/job_card.py
index bce5b90..81c5eb9 100644
--- a/erpnext/manufacturing/doctype/job_card/job_card.py
+++ b/erpnext/manufacturing/doctype/job_card/job_card.py
@@ -141,9 +141,6 @@
 
 		self.db_set('status', status)
 
-def update_job_card_reference(name, fieldname, value):
-	frappe.db.set_value('Job Card', name, fieldname, value)
-
 @frappe.whitelist()
 def make_material_request(source_name, target_doc=None):
 	def update_item(obj, target, source_parent):
diff --git a/erpnext/stock/doctype/material_request/material_request.py b/erpnext/stock/doctype/material_request/material_request.py
index 42c8370..df27a59 100644
--- a/erpnext/stock/doctype/material_request/material_request.py
+++ b/erpnext/stock/doctype/material_request/material_request.py
@@ -15,7 +15,6 @@
 from erpnext.manufacturing.doctype.work_order.work_order import get_item_details
 from erpnext.buying.utils import check_for_closed_status, validate_for_items
 from erpnext.stock.doctype.item.item import get_item_defaults
-from erpnext.manufacturing.doctype.job_card.job_card import update_job_card_reference
 
 from six import string_types
 
@@ -93,9 +92,6 @@
 		if self.material_request_type == 'Purchase':
 			self.validate_budget()
 
-		if self.job_card:
-			update_job_card_reference(self.job_card, 'material_request', self.name)
-
 	def before_save(self):
 		self.set_status(update=True)
 
@@ -148,8 +144,6 @@
 	def on_cancel(self):
 		self.update_requested_qty()
 		self.update_requested_qty_in_production_plan()
-		if self.job_card:
-			update_job_card_reference(self.job_card, 'material_request', None)
 
 	def update_completed_qty(self, mr_items=None, update_modified=True):
 		if self.material_request_type == "Purchase":
diff --git a/erpnext/stock/doctype/stock_entry/stock_entry.py b/erpnext/stock/doctype/stock_entry/stock_entry.py
index eb817e1..d4e7b95 100644
--- a/erpnext/stock/doctype/stock_entry/stock_entry.py
+++ b/erpnext/stock/doctype/stock_entry/stock_entry.py
@@ -17,7 +17,6 @@
 from erpnext.stock.doctype.serial_no.serial_no import update_serial_nos_after_submit, get_serial_nos
 
 import json
-from erpnext.manufacturing.doctype.job_card.job_card import update_job_card_reference
 
 from six import string_types, itervalues, iteritems
 
@@ -89,10 +88,6 @@
 		if self.work_order and self.purpose == "Manufacture":
 			self.update_so_in_serial_number()
 
-
-		if self.job_card:
-			update_job_card_reference(self.job_card, 'stock_entry', self.name)
-
 	def on_cancel(self):
 
 		if self.purchase_order and self.purpose == "Subcontract":
@@ -107,9 +102,6 @@
 		self.make_gl_entries_on_cancel()
 		self.update_cost_in_project()
 
-		if self.job_card:
-			update_job_card_reference(self.job_card, 'stock_entry', None)
-
 	def set_job_card_data(self):
 		if self.job_card and not self.work_order:
 			data = frappe.db.get_value('Job Card',