_include.php: Make sure that the session is initialized before any output.

git-svn-id: https://simplesamlphp.googlecode.com/svn/trunk@1596 44740490-163a-0410-bde0-09ae8108e29a

www/_include.php

@@ -95,6 +95,7 @@ if (!file_exists($configdir . '/config.php')) {
 
 SimpleSAML_Configuration::setConfigDir($configdir);
 
-
+/* Make sure that the session is initialized before any output. */
+SimpleSAML_Session::getInstance();
 
 ?>
\ No newline at end of file