debian/libu2f-udev.metainfo.*: Relicense under LGPL-2.1+

The metadata generated by the Python script is derived from udev rules
that are themselves under LGPL-2.1+

While it's arguably a collection of facts (and non-copyrightable),
it makes things easier if we claim the same license for the generating
scripts, input data, and generated artifacts.

debian/copyright

@@ -15,6 +15,12 @@ Copyright: Copyright (c) 2013-2015 Yubico AB
            Copyright (c) 2016-2018 Nicolas Braud-Santoni <nicolas@braud-santoni.eu>
 License: GPL-3+
 
+Files: debian/libu2f-udev.metainfo.*
+Copyright: Copyright (c) 2018-2019 Nicolas Braud-Santoni <nicolas@braud-santoni.eu>
+License: LGPL-2.1+
+Comment:
+ Those files generate AppStream metadata, based (in part) on the udev
+ rules shipped by the package, which are themselves under LGPL-2.1+.
 
 License: GPL-3+
  This program is free software; you can redistribute it and/or modify

debian/libu2f-udev.metainfo.xml

 <?xml version="1.0" encoding="UTF-8"?>
 <component>
   <id>libu2f-udev</id>
-  <metadata_license>ISC</metadata_license>
+  <metadata_license>LGPL-2.1+</metadata_license>
   <name>libu2f-udev</name>
   <summary>Provide user access to U2F devices</summary>
   <description>