Fix build. There was a bug in SimpleSAML\Utils\HTTP::parseQueryString() that...

Fix build. There was a bug in SimpleSAML\Utils\HTTP::parseQueryString() that was producing an empty parameter with an empty value when the query string was empty.

lib/SimpleSAML/Utils/HTTP.php

@@ -830,6 +830,10 @@ class HTTP
         }
 
         $res = array();
+        if (empty($query_string)) {
+            return $res;
+        }
+
         foreach (explode('&', $query_string) as $param) {
             $param = explode('=', $param);
             $name = urldecode($param[0]);