Update system/core/Log.php

Don't print no script access code into log file if log file is not .php anymore.
diff --git a/system/core/Log.php b/system/core/Log.php
index abc7b24..7b2082a 100644
--- a/system/core/Log.php
+++ b/system/core/Log.php
@@ -162,7 +162,10 @@
 		if ( ! file_exists($filepath))
 		{
 			$newfile = TRUE;
-			$message .= '<'."?php defined('BASEPATH') OR exit('No direct script access allowed'); ?".">\n\n";
+			if($this->_log_ext === 'php')
+			{
+				$message .= '<'."?php defined('BASEPATH') OR exit('No direct script access allowed'); ?".">\n\n";
+			}
 		}
 
 		if ( ! $fp = @fopen($filepath, FOPEN_WRITE_CREATE))