Revert "jQuery3: adding migration tool for debugging"

This reverts commit 0dad0592.

Change-Id: I2b7d842f88f89a980f68c8f50556a3f01d468402

htdocs/lib/web.php

@@ -219,7 +219,6 @@ function smarty($javascript = array(), $headers = array(), $pagestrings = array(
     // Make jQuery accessible with $j (Mochikit has $)
     $javascript_array[] = $jsroot . 'jquery/jquery.js';
     $headers[] = '<script type="application/javascript">$j=jQuery;</script>';
-    $headers[] = '<script src="https://code.jquery.com/jquery-migrate-3.0.1.js"></script>';
 
     // If necessary, load MathJax configuration
     if (get_config('mathjax')) {