FIX: cross sign disappears after switching a faculty

The cross sign and an ability to drop the selected item are restored.

Improves usability.

~dev_rating/media/js/discipline/general.js

@@ -30,6 +30,7 @@ $(function() {
                 var jProto = $($.parseHTML("<option></option>"));
                 selectSubject.html("");
 
+                selectSubject.append($.parseHTML("<option></option>"));
                 $.each(data, function (key, cur) { 
                     jProto.html(cur.Title).val(cur.ID);
                     selectSubject.append(jProto.clone());	
@@ -38,6 +39,8 @@ $(function() {
         ).always(
             function(success)
             {
+                if (selectSubject.children().first().is(":selected"))
+                    selectSubject.select2({placeholder: "Выберите предмет", allowClear: true});
                 selectSubject.removeAttr("disabled");
             }
         );