Remove the X in the drive tree

www/common/drive-ui.js

@@ -3864,6 +3864,7 @@ define([
 
             $tree.html('');
 
+            /*
             $(h('button.fa.fa-times.cp-close-button', {
                 title: Messages.filePicker_close
             })).click(function (e) {
@@ -3871,6 +3872,7 @@ define([
                 $tree.hide();
                 checkCollapseButton();
             }).appendTo($tree);
+            */
 
             var $div = $('<div>', {'class': 'cp-app-drive-tree-categories-container'})
                 .appendTo($tree);