cast-ballot: do not fail when no confirmation e-mail is sent
cast-ballot: do not fail when no confirmation e-mail is sent

The users therefore know that their ballots have been received by the
server, even though they do not get a confirmation e-mail.

glondu/belenios,glondu/belenios,glondu/belenios,glondu/belenios,glondu/belenios