Now that cck is using new cache table, the pollfield module needs to clear that cache instead of the general one

#130041 had to restructure the form array to keep the field name as a single top-level form element to keep from breaking fieldgroup.

- #130041 make sure pollfield does not require questions when field is not required

The pollfield module creates a CCK field that behaves like the core poll module but can be added to any content type.