python/aqmp: add explicit GPLv2 license to legacy.py

The legacy.py module is heavily based on the QMP module by Luiz
Capitulino (et al) which is licensed as explicit GPLv2-only. The async
QMP package is currently licensed similarly, but I intend to relicense
the async package to the more flexible LGPLv2+.

In preparation for that change, make the license on legacy.py explicit.

Signed-off-by: John Snow <jsnow@redhat.com>
Message-id: 20220325200438.2556381-2-jsnow@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>
diff --git a/python/qemu/aqmp/legacy.py b/python/qemu/aqmp/legacy.py
index 46026e9..f86cb29 100644
--- a/python/qemu/aqmp/legacy.py
+++ b/python/qemu/aqmp/legacy.py
@@ -4,6 +4,17 @@
 This class pretends to be qemu.qmp.QEMUMonitorProtocol.
 """
 
+#
+# Copyright (C) 2009-2022 Red Hat Inc.
+#
+# Authors:
+#  Luiz Capitulino <lcapitulino@redhat.com>
+#  John Snow <jsnow@redhat.com>
+#
+# This work is licensed under the terms of the GNU GPL, version 2.  See
+# the COPYING file in the top-level directory.
+#
+
 import asyncio
 from typing import (
     Any,