maint: fix license on polkit script

As approved here:
https://www.redhat.com/archives/libvir-list/2012-October/msg00701.html

* daemon/libvirtd.policy.in: Use LGPLv2+ license.

daemon/libvirtd.policy.in

@@ -6,10 +6,22 @@
 <!--
 Policy definitions for libvirt daemon
 
-Copyright (c) 2007 Daniel P. Berrange <berrange redhat com>
+Copyright (C) 2012 Red Hat, Inc.
+Copyright (C) 2007 Daniel P. Berrange <berrange redhat com>
 
-libvirt is licensed to you under the GNU Lesser General Public License
-version 2. See COPYING for details.
+This library is free software; you can redistribute it and/or
+modify it under the terms of the GNU Lesser General Public
+License as published by the Free Software Foundation; either
+version 2.1 of the License, or (at your option) any later version.
+
+This library is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public
+License along with this library.  If not, see
+<http://www.gnu.org/licenses/>.
 -->
 
 <policyconfig>