Remove unused timestampThreshold variable

Fixes: commit 9b6fe92

Author: pabs3

dashboard/finished.html

@@ -43,7 +43,6 @@
 	<script>
 		var table;
 		var reloadInterval = 600 * 1000; // 10 minutes
-		var timestampThreshold = 60 * 5 * 1000;
 		var showNicks = (location.search.indexOf("?showNicks=") != -1) || (location.search.indexOf("&showNicks=") != -1);
 		function initTable() {
 			if (showNicks) $('#queued_by').show();