Error on mixed groups when nis schema not present

I get this error when configuring FD for the first time:

 Your schema is configured to support mixed groups, but this plugin is not present.

But I did not use miwed groups in my schema. I just don't have the nis schema installed. The error message should be more precise.

(from redmine: issue id 5003, created on 2016-07-12, closed on 2016-08-10)

• Relations:
  • relates #5004
  • relates #5057
• Changesets:
  • Revision e8a8948e on 2016-07-28T14:42:56.000Z:

Fixes #5003 Fixed mixed-groups check

• Revision f6e403be on 2016-07-28T14:43:36.000Z:

Fixes #5003 Fixed mixed-groups check

• Custom Fields:
  • Bug in version: 1.0.14