Always go to the DOM for tooltip and error-tooltip content.

As shown [here][1], [here][2] and [here][3], jQuery caches
data-attributes and doesn't update the cache after the first
read.

With richer forms validation scenarios it's easy to imagine wanting
different kinds of invalid form data triggering different validation
error tooltip messages. FormField and React will ensure that whatever
the validation error message is for the current form data, it is
rendered into the DOM.

Using `.attr('data-tooltip')` and `.attr('data-error-tooltip')`
instead of `.data('tooltip')` and `.data('error-tooltip')` will ensure
that the most recent validation tooltips, i.e. the current values
of the 'data-tooltip' and 'data-error-tooltip' attributes,
will be shown.

[1]: http://forum.jquery.com/topic/jquery-data-caching-of-data-attributes
[2]: https://gist.github.com/mattfeury/3298929
[3]: http://api.jquery.com/data/#data-html5
Refresh error tooltip when FormField is consistently invalid and validation message changed