Drop the unused  parameter from log_message() / CI_Log::write_log()
diff --git a/system/core/Log.php b/system/core/Log.php
index e4d72b5..20bc559 100644
--- a/system/core/Log.php
+++ b/system/core/Log.php
@@ -143,7 +143,7 @@
 	 * @param	bool	whether the error is a native PHP error
 	 * @return	bool
 	 */
-	public function write_log($level, $msg, $php_error = FALSE)
+	public function write_log($level, $msg)
 	{
 		if ($this->_enabled === FALSE)
 		{