cint for Item field has_variants (#13916)

* convert none type value to int

* Fix typo
diff --git a/erpnext/stock/doctype/item/item.py b/erpnext/stock/doctype/item/item.py
index 9b63974..203458e 100644
--- a/erpnext/stock/doctype/item/item.py
+++ b/erpnext/stock/doctype/item/item.py
@@ -641,9 +641,9 @@
 
 	def validate_stock_exists_for_template_item(self):
 		if self.stock_ledger_created() and self._doc_before_save:
-			if (self._doc_before_save.has_variants != self.has_variants
+			if (cint(self._doc_before_save.has_variants) != cint(self.has_variants)
 				or self._doc_before_save.variant_of != self.variant_of):
-				frappe.throw(_("Cannot change Variant properties after stock transction. You will have to make a new Item to do this.").format(self.name),
+				frappe.throw(_("Cannot change Variant properties after stock transaction. You will have to make a new Item to do this.").format(self.name),
 					StockExistsForTemplate)
 
 			if self.has_variants or self.variant_of: