Remove the storageDriver span from page, so that IE6/7 won't throw error...

[lingyan]

..., when someone tries to access getAttribute property on this span element.

For example, if you use attribute css selector on the page via YUI's Y.all(), e.g. Y.all('[data-attr]') in IE6/7, you would encounter this problem of seeing an JS error saying "Object does not support this property or method". That is because YUI's selector-css2's _filterNodes function tries to access getAttribute of the storageDriver element, which is a span element with added behavior: http://yuilibrary.com/yui/docs/api/files/dom_js_selector-css2.js.html#l161

@rgrove To reproduce the original problem, you can comment out the changes made in src/storage-lite.js, and run unit test. The newly added test "testIE67GetAttribute" would fail with the JS error mentioned above.