Update default cookie message to match the govuk template
Update default cookie message to match the govuk template

This now matches the default message, shown in the GOV.UK template.
https://github.com/alphagov/govuk_template/blob/master/source/views/layo
uts/govuk_template.html.erb#L73

This has also been updated in the govuk prototype kit.

gavboulton/govuk_elements,gavboulton/govuk_elements,alphagov/govuk_elements,joelanman/govuk_elements,alphagov/govuk_elements,gavboulton/govuk_elements,alphagov/govuk_elements,alphagov/govuk_elements,joelanman/govuk_elements,gavboulton/govuk_elements