Dropdown menu in justified button-group

It seems that dropdown-menu in justified button-group appears at the far
left of the group. Check the problem in [Bootstrap
site](http://getbootstrap.com/components/#btn-groups-justified).

less/button-groups.less

@@ -216,6 +216,10 @@
   > .btn-group .btn {
     width: 100%;
   }
+
+  > .btn-group .dropdown-menu {
+    left: auto;
+  }
 }