libosmo-mgcp-client is GPLv2+, not AGPLv3+

The client library should be usable to all GPLv2/v3/AGPLv2/v3 programs,
so like our general project practises, let's put it under
GPLv2-or-later.  I believe this was unintentional from the beginning.

Our general policy has been:
* libraries under GPLv2-or-later
* applications under AGPLv3-or-later

Change-Id: I29ed7edc510dba67d28b9247aecb4d6d5d25cc0c
diff --git a/debian/copyright b/debian/copyright
index 83e29df..467435f 100644
--- a/debian/copyright
+++ b/debian/copyright
@@ -21,6 +21,25 @@
  You should have received a copy of the GNU Affero General Public License
  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
+Files:     src/libosmo-mgcp-client/* include/osmocom/mgcp_client/*
+Copyright: 2016 by sysmocom s.m.f.c. GmbH <info@sysmocom.de>
+           Based on OpenBSC interface to quagga VTY (libmsc/vty_interface_layer3.c)
+           2009 by Harald Welte <laforge@gnumonks.org>
+           2009-2011 by Holger Hans Peter Freyther
+License:   GPL-2.0+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 2 of the License, or
+ (at your option) any later version.
+ .
+ This program 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 General Public License for more details.
+ .
+ You should have received a copy of the GNU General Public License
+ along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
 Files:     src/libosmo-legacy-mgcp/g711common.h
 Copyright: 2000 Abramo Bagnara <abramo@alsa-project.org>
 License:   GPL-2.0+