Unbreak links on monitoring splash page
Unbreak links on monitoring splash page

Missed an assignment of `$domain` in PR #300.

These links won't go to the correct place in staging because `app_domain`
points to production. However we should already know that.

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