Use proper path

Fixes https://github.com/owncloud/core/issues/24407

apps/files_external/lib/storage/google.php

@@ -445,7 +445,7 @@ class Google extends \OC\Files\Storage\Common {
 							$response = $client->get($downloadUrl, [
 								'headers' => $httpRequest->getRequestHeaders(),
 								'stream' => true,
-								'verify' => __DIR__ . '/../3rdparty/google-api-php-client/src/Google/IO/cacerts.pem',
+								'verify' => __DIR__ . '/../../3rdparty/google-api-php-client/src/Google/IO/cacerts.pem',
 							]);
 						} catch (RequestException $e) {
 							if(!is_null($e->getResponse())) {