Revert "TabIndex of 500 is illegal as per AODA, it has been changed to 0 (#1524)" (#1526)

This reverts commit 39423eed9988991672e268af9e313330185489bc.

js/fileinput.js

@@ -7,8 +7,6 @@
  *
  * Licensed under the BSD-3-Clause
  * https://github.com/kartik-v/bootstrap-fileinput/blob/master/LICENSE.md
- *
- * Note: Tabindex of 500 is illegal as per AODA, it has been changed to 0
  */
 (function (factory) {
     'use strict';
@@ -1407,17 +1405,17 @@
             tClose = $h.closeButton('fileinput-remove');
             tFileIcon = '<i class="glyphicon glyphicon-file"></i>';
             // noinspection HtmlUnknownAttribute
-            tCaption = '<div class="file-caption form-control {class}" tabindex="0">\n' +
+            tCaption = '<div class="file-caption form-control {class}" tabindex="500">\n' +
                 '  <span class="file-caption-icon"></span>\n' +
                 '  <input class="file-caption-name" onkeydown="return false;" onpaste="return false;">\n' +
                 '</div>';
             //noinspection HtmlUnknownAttribute
-            tBtnDefault = '<button type="{type}" tabindex="0" title="{title}" class="{css}" ' +
+            tBtnDefault = '<button type="{type}" tabindex="500" title="{title}" class="{css}" ' +
                 '{status}>{icon} {label}</button>';
             //noinspection HtmlUnknownTarget,HtmlUnknownAttribute
-            tBtnLink = '<a href="{href}" tabindex="0" title="{title}" class="{css}" {status}>{icon} {label}</a>';
+            tBtnLink = '<a href="{href}" tabindex="500" title="{title}" class="{css}" {status}>{icon} {label}</a>';
             //noinspection HtmlUnknownAttribute
-            tBtnBrowse = '<div tabindex="0" class="{css}" {status}>{icon} {label}</div>';
+            tBtnBrowse = '<div tabindex="500" class="{css}" {status}>{icon} {label}</div>';
             tModalMain = '<div id="' + $h.MODAL_ID + '" class="file-zoom-dialog modal fade" ' +
                 'tabindex="-1" aria-labelledby="' + $h.MODAL_ID + 'Label"></div>';
             tModal = '<div class="modal-dialog modal-lg{rtl}" role="document">\n' +