Bugid: 101588 -- fixed editing WikiaPoll in RTE

Fix for a [P3](https://wikia.fogbugz.com/default.asp?101588) bug -- unable to update WikiaPoll in RTE. The cause of the bug was looking for <code>pollid</code> instead of <code>pollId</code>. Additionally, I added caching of <code>#CreateWikiaPoll</code> DOM element.