MDL-20717 GPL version 3 at the Copyright notice during the installation

The new string 'gpl3' replaces the legacy string 'gpl'. Once we have
proper lang branching, 'gpl' string should be removed from 2.0/HEAD.

admin/cli/install.php

@@ -465,7 +465,7 @@
         cli_separator();
         cli_heading(get_string('copyrightnotice'));
         echo "Moodle  - Modular Object-Oriented Dynamic Learning Environment\n";
-        echo get_string('gpl')."\n\n";
+        echo get_string('gpl3')."\n\n";
         echo get_string('doyouagree')."\n";
         $prompt = get_string('cliyesnoprompt', 'admin');
         $input = cli_input($prompt, '', array(get_string('clianswerno', 'admin'), get_string('cliansweryes', 'admin')));

admin/index.php

@@ -126,7 +126,7 @@
         echo $OUTPUT->header();
         echo $OUTPUT->heading('<a href="http://moodle.org">Moodle</a> - Modular Object-Oriented Dynamic Learning Environment');
         echo $OUTPUT->heading(get_string('copyrightnotice'));
-        $copyrightnotice = text_to_html(get_string('gpl'));
+        $copyrightnotice = text_to_html(get_string('gpl3'));
         $copyrightnotice = str_replace('target="_blank"', 'onclick="this.target=\'_blank\'"', $copyrightnotice); // extremely ugly validation hack
         echo $OUTPUT->box($copyrightnotice, 'copyrightnotice');
         echo '<br />';

lang/en_utf8/moodle.php

@@ -772,6 +772,19 @@
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 
+See the Moodle License information page for full details:
+http://docs.moodle.org/en/License';
+$string['gpl3'] = 'Copyright (C) 1999 onwards Martin Dougiamas (http://moodle.com)
+
+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 3 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 Moodle License information page for full details:
 http://docs.moodle.org/en/License';
 $string['grade'] = 'Grade';