AUI-1114 Check boolean first than dom operations for performance

src/aui-tree/js/aui-tree-view.js

@@ -783,7 +783,7 @@ var TreeViewDD = A.Component.create({
             // cannot drop the dragged element into any of its children
             // nor above an undraggable element
             // using DOM contains method for performance reason
-            if (!dragNode.contains(dropNode) && !!dropTreeNode.get(DRAGGABLE)) {
+            if (!!dropTreeNode.get(DRAGGABLE) && !dragNode.contains(dropNode)) {
                 // nArea splits the height in 3 areas top/center/bottom these
                 // areas are responsible for defining the state when the mouse
                 // is over any of them