Don't try to use backgroundjobs before the installtion is done

lib/base.php

@@ -560,13 +560,15 @@ class OC {
 	 * register hooks for the cache
 	 */
 	public static function registerCacheHooks() {
-		// register cache cleanup jobs
-		try { //if this is executed before the upgrade to the new backgroundjob system is completed it will throw an exception
-			@\OCP\BackgroundJob::registerJob('OC_Cache_FileGlobalGC');
-		} catch (Exception $e) {
+		if (OC_Config::getValue('installed', false)) { //don't try to do this before we are properly setup
+			// register cache cleanup jobs
+			try { //if this is executed before the upgrade to the new backgroundjob system is completed it will throw an exception
+				\OCP\BackgroundJob::registerJob('OC_Cache_FileGlobalGC');
+			} catch (Exception $e) {
 
+			}
+			OC_Hook::connect('OC_User', 'post_login', 'OC_Cache_File', 'loginListener');
 		}
-		OC_Hook::connect('OC_User', 'post_login', 'OC_Cache_File', 'loginListener');
 	}
 
 	/**