[#70828818] Mount extra disk for mirrorer-1
[#70828818] Mount extra disk for mirrorer-1

Mount the new disk added in gds/govuk-provisioning@cc1ad01 to the location
that `govuk_update_mirror` expects. Puppet runs will fail until the machines
are re-provisioned (with the extra disk) in staging and production. This
won't apply to preview because `use_hiera_disks` is disabled.

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