also use updatedir for cleanup of backups

Signed-off-by: Arthur Schiwon <blizzz@arthur-schiwon.de>

core/BackgroundJobs/BackgroundCleanupUpdaterBackupsJob.php

@@ -45,14 +45,14 @@ class BackgroundCleanupUpdaterBackupsJob extends QueuedJob {
 	 * This job cleans up all backups except the latest 3 from the updaters backup directory
 	 */
 	public function run($arguments) {
-		$dataDir = $this->config->getSystemValue('datadirectory', \OC::$SERVERROOT . '/data');
+		$updateDir = $this->config->getSystemValue('updatedirectory', null) ?? $this->config->getSystemValue('datadirectory', \OC::$SERVERROOT . '/data');
 		$instanceId = $this->config->getSystemValue('instanceid', null);
 
 		if (!is_string($instanceId) || empty($instanceId)) {
 			return;
 		}
 
-		$updaterFolderPath = $dataDir . '/updater-' . $instanceId;
+		$updaterFolderPath = $updateDir . '/updater-' . $instanceId;
 		$backupFolderPath = $updaterFolderPath . '/backups';
 		if (file_exists($backupFolderPath)) {
 			$this->log->info("$backupFolderPath exists - start to clean it up");