Update assets to v9.9.3

Fixed broken data attributes handling for IE<9.

Author: opti

app/assets/javascripts/jquery-fileupload/jquery.fileupload.js

@@ -1,5 +1,5 @@
 /*
- * jQuery File Upload Plugin 5.42.2
+ * jQuery File Upload Plugin 5.42.3
  * https://github.com/blueimp/jQuery-File-Upload
  *
  * Copyright 2010, Sebastian Tschan
@@ -1344,18 +1344,19 @@
         _initDataAttributes: function () {
             var that = this,
                 options = this.options,
-                clone = $(this.element[0].cloneNode(false)),
-                data = clone.data();
-            // Avoid memory leaks:
-            clone.remove();
+                data = this.element.data();
             // Initialize options set via HTML5 data-attributes:
             $.each(
-                data,
-                function (key, value) {
-                    var dataAttributeName = 'data-' +
-                        // Convert camelCase to hyphen-ated key:
-                        key.replace(/([a-z])([A-Z])/g, '$1-$2').toLowerCase();
-                    if (clone.attr(dataAttributeName)) {
+                this.element[0].attributes,
+                function (index, attr) {
+                    var key = attr.name.toLowerCase(),
+                        value;
+                    if (/^data-/.test(key)) {
+                        // Convert hyphen-ated key to camelCase:
+                        key = key.slice(5).replace(/-[a-z]/g, function (str) {
+                            return str.charAt(1).toUpperCase();
+                        });
+                        value = data[key];
                         if (that._isRegExpOption(key, value)) {
                             value = that._getRegExp(value);
                         }