paper: add reddish background to ajax error message

mercurial/templates/static/style-paper.css

@@ -403,3 +403,6 b' ul#graphnodes li .info {'
   from { background-color: #A0CEFF; } to {  }
 }
 
+.scroll-loading-error {
+    background-color: #FFCCCC !important;
+}