Stop Varnish from removing GOVUK-Request-Id
Stop Varnish from removing GOVUK-Request-Id

GOV.UK-Request-Id is now set by the CDN so there's no reason
to remove it in the middle of the stack.

alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet