Geo: Avoid locking yourself out when adding a GeoNode
This is a fix to https://gitlab.com/gitlab-org/gitlab-ee/issues/374 for Geo (#76).
It was possible to lock yourself out on the primary node, as in this example:
- My GitLab domain is example.com
- I go to the Geo nodes admin area for the first time (no node yet registered)
- I register a new node http://example.com but I forget to mark it as primary
- The GitLab server is now read-only and I cannot undo my action because of that
- Users start e-mailing me death threats because they cannot use GitLab
This should be in 8.5 too. cc @DouweM