[minor] replaced db_save by db_update and added patch to remove the indexes on tabBin

erpnext/patches/v8_0/delete_bin_indexes.py

@@ -0,0 +1,16 @@
+# Copyright (c) 2017, Frappe and Contributors
+# License: GNU General Public License v3. See license.txt
+# -*- coding: utf-8 -*-
+
+from __future__ import unicode_literals
+import frappe
+
+def execute():
+	# delete bin indexes
+	unwanted_indexes = ["item_code", "warehouse"]
+
+	for k in unwanted_indexes:
+		try:
+			frappe.db.sql("drop index {0} on `tabBin`".format(k))
+		except:
+			pass