[Minor] Treat no valid elements as permanent spf error

src/plugins/spf.c

@@ -511,9 +511,9 @@ spf_plugin_callback (struct spf_resolved *record, struct rspamd_task *task,
 				1,
 				NULL);
 	}
-	else if (record && record->elts->len == 0 && record->temp_failed) {
+	else if (record && record->elts->len == 0) {
 		rspamd_task_insert_result (task,
-				spf_module_ctx->symbol_dnsfail,
+				spf_module_ctx->symbol_permfail,
 				1,
 				NULL);
 	}