saml2/sp/initSSO: Set $reachableIDPs to silence a warning.

git-svn-id: https://simplesamlphp.googlecode.com/svn/trunk@1833 44740490-163a-0410-bde0-09ae8108e29a

www/saml2/sp/initSSO.php

@@ -24,6 +24,8 @@ if (empty($_GET['RelayState'])) {
 	SimpleSAML_Utilities::fatalError($session->getTrackID(), 'NORELAYSTATE');
 }
 
+$reachableIDPs = array();
+
 try {
 
 	$idpentityid = isset($_GET['idpentityid']) ? $_GET['idpentityid'] : $config->getString('default-saml20-idp', NULL) ;