[SSSD] [sssd PR#78][comment] ipa: Nested netgroups do not work

[fidencio]

URL: https://github.com/SSSD/sssd/pull/78
Title: #78: ipa: Nested netgroups do not work

celestian commented:
"""
Code LGTM.
CI passed: http://sssd-ci.duckdns.org/logs/job/56/99/summary.html

And I tested it manually:
```
Setup FreeIPA server and do the following:
1. create two netgroups - ng1, ng2
2. add user1 to ng1
3. add user2 to ng2
4. add ng2 to ng1 (make ng2 member of ng1)
5. run command:
$ getent netgroup ng1

Wrong output: you do not see netgroup members
Correct output: You shoudl see all members of ng1 and ng2
```

@jhrozek , I give conitional ACK to this patch if downstream tests passed.
"""

See the full comment at https://github.com/SSSD/sssd/pull/78#issuecomment-259938864