No members in a group when syncing groups in OpenShift with LDAP on IPA

Issue

OpenShift syncing groups with LDAP can find user groups but not their members when bind dn and passwords aren't specified.

With ldap_group_sync.yaml:

url: ldap://10.0.0.0:389 
insecure: true 
ca: my-ldap-ca-bundle.crt  
rfc2307:
...

The oadm groups sync got no users:

$ oadm groups sync --sync-config=ldap_group_sync.yaml
apiVersion: v1
items:
- apiVersion: v1
  kind: Group
  metadata:
    annotations:
      openshift.io/ldap.sync-time: 2016-08-02T17:26:08-0400
      openshift.io/ldap.uid: cn=admins,dc=example,dc=com
      openshift.io/ldap.url: localhost:389
    creationTimestamp: null
    labels:
      openshift.io/ldap.host: localhost
    name: admins
  users: null
kind: List
metadata: {}