Fix a couple of issues reported by scrutinizer.

lib/SimpleSAML/SessionHandlerStore.php

@@ -54,7 +54,7 @@ class SessionHandlerStore extends SessionHandlerCookie
 
         $session = $this->store->get('session', $sessionId);
         if ($session !== null) {
-            assert($session instanceof SimpleSAML_Session);
+            assert($session instanceof \SimpleSAML_Session);
             return $session;
         }
 

lib/SimpleSAML/XML/Signer.php

@@ -302,6 +302,7 @@ class Signer
             $options
         );
 
+        /** @var \RobRichards\XMLSecLibs\XMLSecurityKey $this->privateKey */
         $objXMLSecDSig->sign($this->privateKey);