Remove some obsolete logic

Now that the scroller div has its own vertical scrollbar, we no longer
need to explicitly update the scrollbar during updateDisplay.

lib/codemirror.js

@@ -1100,16 +1100,7 @@ var CodeMirror = (function() {
         return heightChanged;
       }
 
-      if (options.lineWrapping) {
-        checkHeights();
-        var scrollHeight = needsScrollbar();
-        var shouldHaveScrollbar = scrollHeight ? "block" : "none";
-        if (scrollbar.style.display != shouldHaveScrollbar) {
-          scrollbar.style.display = shouldHaveScrollbar;
-          if (scrollHeight) scrollbarInner.style.height = scrollHeight + "px";
-          checkHeights();
-        }
-      }
+      if (options.lineWrapping) checkHeights();
 
       gutter.style.display = gutterDisplay;
       if (different || gutterDirty) {