js/loader: postpone redirection handling

Redirections should not be executed unless the original request has been
terminated and removed from pending requests.

fixes #6989

public/js/icinga/loader.js

@@ -329,8 +329,7 @@
                 this.icinga.ui.reloadCss();
             }
 
-            var redirect = req.getResponseHeader('X-Icinga-Redirect');
-            if (this.processRedirectHeader(req)) return;
+            if (req.getResponseHeader('X-Icinga-Redirect')) return;
 
             // div helps getting an XML tree
             var $resp = $('<div>' + req.responseText + '</div>');
@@ -567,6 +566,7 @@
             delete this.requests[req.$target.attr('id')];
             this.icinga.ui.fadeNotificationsAway();
 
+            this.processRedirectHeader(req);
 
             if (typeof req.loadNext !== 'undefined') {
                 if ($('#col2').length) {