Merge pull request #2875 from Hypolite/bug/profiler-small-bugfix

Fix $a to #this in save_timestamp

boot.php

@@ -1100,7 +1100,7 @@ class App {
 	}
 
 	function save_timestamp($stamp, $value) {
-		if (!isset($a->config['system']['profiler']) || !$a->config['system']['profiler'])
+		if (!isset($this->config['system']['profiler']) || !$this->config['system']['profiler'])
 			return;
 
 		$duration = (float)(microtime(true)-$stamp);