Not only we have to reset the vdagent clipboards serial state, but also
the current QEMU clipboards info serial (the value is currently used by
qemu_clipboard_check_serial, only used by -display dbus).

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20220912102455.111765-5-marcandre.lureau@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>