[fix] permissions not checked to change state of a redirect

This PRs tries to fix some issues found after merging https://github.com/joomla/joomla-cms/pull/4609#discussion_r18748245

* I'm deprecating `JHtmlRedirect::published()` as the fix we applied is a bit tricky
* I'm creating a new function `JHtmlRedirect::status()` as replacement of the previous method
* I'm replacing the only existing call to `JHtml::_('redirect.published'` to use now `JHtml::_('redirect.status'`
* When replacing the call I realised that the `$canChange` is not checked to display the icon. That + having a default value of true made it always clickable by the user.

cc / @roland-d