tests/qtest: Fix LGPL information in the file headers

It's either "GNU *Library* General Public License version 2" or "GNU
Lesser General Public License version *2.1*", but there was no "version
2.0" of the "Lesser" license. So assume that version 2.1 is meant here.

Message-Id: <20200605100645.6506-1-thuth@redhat.com>
Reviewed-by: Laurent Vivier <lvivier@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>

tests/qtest/fuzz/qos_fuzz.c

@@ -5,7 +5,7 @@
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
- * License version 2 as published by the Free Software Foundation.
+ * License version 2.1 as published by the Free Software Foundation.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of