Add CSRF protection to upgrader

include/upgrader/prereq.inc.php

@@ -27,6 +27,7 @@ if(!defined('OSTSCPINC') || !$thisstaff || !$thisstaff->isAdmin()) die('Access D
             </ul>
             <div id="bar">
                 <form method="post" action="upgrade.php" id="prereq">
+                    <?php csrf_token(); ?>
                     <input type="hidden" name="s" value="prereq">
                     <input class="btn"  type="submit" name="submit" value="Start Upgrade Now &raquo;">
                 </form>

include/upgrader/rename.inc.php

@@ -18,6 +18,7 @@ if(!defined('OSTSCPINC') || !$thisstaff || !$thisstaff->isAdmin()) die('Access D
             <p>Please refer to the <a target="_blank" href="http://osticket.com/wiki/Upgrade_and_Migration">Upgrade Guide</a> for more information.</p>
             <div id="bar">
                 <form method="post" action="upgrade.php">
+                    <?php csrf_token(); ?>
                     <input type="hidden" name="s" value="prereq">
                     <input class="btn" type="submit" name="submit" value="Continue &raquo;">
                 </form>

include/upgrader/upgrade.inc.php

@@ -18,6 +18,7 @@ $action=$upgrader->getNextAction();
             </ul>
             <div id="bar">
                 <form method="post" action="upgrade.php" id="upgrade">
+                    <?php csrf_token(); ?>
                     <input type="hidden" name="s" value="upgrade">
                     <input type="hidden" name="sh" value="<?php echo $upgrader->getSchemaSignature(); ?>">
                     <input class="btn"  type="submit" name="submit" value="Do It Now!">