This way screen reader users will know which record they're going to
access when focusing on a link to a certain action. Otherwise they'd
hear something like "Edit, link", and they wouldn't know which record
they'll end up editing if they follow the link.
Show a flash message that it's not possible to delete booth shifts
when they have associated recounts or partial results. Before an
execption was raised.
Make sure we create the Poll::OfficerAssignments in the same order the
booth_assignments where previously created. So the spec "Poll::Shift
officer_assignments creates and destroy corresponding
officer_assignments does" not fail.
