Cause: Some LDAP deployments contain a group with GID=0 that acts like a "root" group. Previously, SSSD would treat the GID of 0 as an error.
Consequence: The whole group processing operation was aborted
Fix: Groups with GID=0 are examined to process any possible nested groups but are not returned
Result: SSSD handled deployments that contain groups with GID=0 gracefully