tweak XSS via hover label test

- the malicious <img onerror=""> tag is now gone!

Author: etpinard

test/jasmine/tests/hover_label_test.js

@@ -248,7 +248,7 @@ describe('hover info', function() {
 
             assertHoverLabelContent({
                 nums: '1\nhover text',
-                name: '<img src=x o...',
+                name: '',
                 axis: '0.388'
             });
         });