Modify legend_scroll_test to match bug fix

Author: alexshoe

test/jasmine/tests/legend_scroll_test.js

@@ -101,7 +101,7 @@ describe('The legend', function() {
             var initialDataScroll = getScroll(gd);
             var wheelDeltaY = 100;
             var finalDataScroll = Lib.constrain(initialDataScroll +
-                wheelDeltaY / scrollBarYMax * scrollBoxYMax,
+                ((wheelDeltaY / scrollBoxYMax) * scrollBarYMax),
                 0, scrollBoxYMax);
 
             legend.dispatchEvent(scrollTo(wheelDeltaY));