[fix]fix name definition in old patch (#6841)

diff --git a/erpnext/patches/v5_1/rename_roles.py b/erpnext/patches/v5_1/rename_roles.py
index 452c800..26208aa 100644
--- a/erpnext/patches/v5_1/rename_roles.py
+++ b/erpnext/patches/v5_1/rename_roles.py
@@ -5,5 +5,5 @@
 		frappe.rename_doc("Role", "Material User", "Stock User")
 	if not frappe.db.exists("Role", "Stock Manager"):
 		frappe.rename_doc("Role", "Material Manager", "Stock Manager")
-	if not frappe.db.exists("Role", "Stock Manager"):
+	if not frappe.db.exists("Role", "Item Manager"):
 		frappe.rename_doc("Role", "Material Master Manager", "Item Manager")