Merge request widget class names update

app/assets/javascripts/merge_request_widget.js.es6

@@ -127,8 +127,8 @@
     MergeRequestWidget.prototype.getMergeStatus = function() {
       return $.get(this.opts.merge_check_url, function(data) {
         var $html = $(data);
-        $('.mr-state-body').replaceWith($html.find('.mr-state-body'));
-        $('.mr-state-footer').replaceWith($html.find('.mr-state-footer'));
+        $('.mr-widget-body').replaceWith($html.find('.mr-widget-body'));
+        $('.mr-widget-footer').replaceWith($html.find('.mr-widget-footer'));
       });
     };