LPS-32056 - User is unable to edit a poll expiration date

Hey @shinnlok,

Attached is an update for http://issues.liferay.com/browse/LPS-32056.

NOTE: I get the following error when trying to save the announcement portlet.  I'm not sure how best to pass the value and the name so I was thinking it might be easier to tweak some stuff on the back end

![screen-capture](https://f.cloud.github.com/assets/860951/609464/ea102072-cd84-11e2-8755-84d7b0fc89b4.png)

Please let me know if you have any questions.  Thanks!