bugfix: We are using namespaces, so SoapClient is not available, we n…

…eed to prepend the root namespace: \SoapClient.

src/SAML2/SOAPClient.php

@@ -107,7 +107,7 @@ public function send(Message $msg, SimpleSAML_Configuration $srcMetadata, Simple
             $options['proxy_port'] = $srcMetadata->getValue('saml.SOAPClient.proxyport');
         }
 
-        $x = new SoapClient(null, $options);
+        $x = new \SoapClient(null, $options);
 
         // Add soap-envelopes
         $request = $msg->toSignedXML();