When a non-bank-csv-thing is uploaded, an error occurs

```
CSV::MalformedCSVError in RegistrationsController#upload

    fails = []
    counter = 0
    CSV.parse(params.require(:csv_file).read.upcase, col_sep: sep, headers: :first_row) do |row|
      match = /GAN(?<event_id>\d+)D(?<id>\d+)A(?<sum>\d+)L(?<ssum>\d+)F/.match(row.to_s)
      next unless match # seems like this is not a Gandalf transfer.

app/controllers/registrations_controller.rb:108:in `upload'
```