ipa: Nested netgroups do not work

[mzidek-gh]

We lowercase the keys to the hash table used to store netgroups
but do not lowercase it when reading the table. This results
in nested netgroups not being found when they should and
the processing fails.

The lowercasing does not seem to be necessary anymore (not
sure if it ever was) so we can skip it.

Resolves:
https://fedorahosted.org/sssd/ticket/3159

[jhrozek]

btw just to help with the review, I also fired up a test job using our downstream tests with a 7.3 package and this test. I'll let you know how the test went.

[celestian]

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.

[jhrozek]

The downstream tests passed (the job ID is 1594128 if anyone wants to take a look).

So I'm adding the Accepted tag.

[jhrozek]

master: ff565da
sssd-1-14: 7de3387
sssd-1-13: 9c4c3a2