do not heal "backend-encrypted" out-of-band with migration (#12556)

backend-encrypted doesn't need to be explicitly healed anymore
since this file is deleted upon upgrade and migration to the
KMS based encrypted config/IAM credentials.

cmd/config-encrypted.go

@@ -183,5 +183,5 @@ func migrateConfigPrefixToEncrypted(objAPI ObjectLayer, encrypted bool) error {
 	if encrypted && GlobalKMS != nil {
 		logger.Info("Migration of encrypted config data completed. All config data is now encrypted.")
 	}
-	return deleteConfig(GlobalContext, globalObjectAPI, backendEncryptedFile)
+	return deleteConfig(GlobalContext, objAPI, backendEncryptedFile)
 }