uploads: handle server errors nicer

rhodecode/public/js/src/rhodecode/comments.js

@@ -729,7 +729,7 b' var CommentsController = function() {'
 
                         if (xhr !== undefined){
                             var httpStatus = xhr.status + " " + xhr.statusText;
-                            if (xhr.status >= 500) {
+                            if (xhr !== undefined && xhr.status >= 500) {
                                 error = httpStatus;
                             }
                         }

rhodecode/templates/files/files_upload.mako

@@ -170,7 +170,7 b''
 
                     if (xhr !== undefined){
                         var httpStatus = xhr.status + " " + xhr.statusText;
-                        if (xhr.status >= 500) {
+                        if (xhr !== undefined && xhr.status >= 500) {
                             error = httpStatus;
                         }
                     }