Some of the code was in its own component, while some of the code
remained in the polls/show view.
Note that we're re-structuring the code a little bit, so it's clear that
the "already voted" messages are only shown when users can vote. Also
note that now the `can?` condition involves the existence of a
`current_user` and that the poll is not expired, so we can simplify the
`voted_in_web` condition.
b48682e3e4