Fixing return value of CakeSession::__startSession(). Once headers we…

…re sent any further session objects would think that the session was not successfully started. Fixes issues in Helper group test. Also fixes #568

cake/libs/cake_session.php

@@ -583,7 +583,7 @@ function __startSession() {
 			if (empty($_SESSION)) {
 				$_SESSION = array();
 			}
-			return false;
+			return true;
 		} elseif (!isset($_SESSION)) {
 			session_cache_limiter ("must-revalidate");
 			session_start();