Fix for command line + sessionhandler php

git-svn-id: https://simplesamlphp.googlecode.com/svn/trunk@1788 44740490-163a-0410-bde0-09ae8108e29a

lib/SimpleSAML/SessionHandlerPHP.php

@@ -83,6 +83,7 @@ class SimpleSAML_SessionHandlerPHP extends SimpleSAML_SessionHandler {
 		/* Check if key exists first to avoid notice-messages in the
 		 * log.
 		 */
+		if (!isset($_SESSION)) return NULL;
 		if(!array_key_exists($key, $_SESSION)) {
 			/* We should return NULL if we don't have that
 			 * key in the session.