providers/ipa/: add_v1_user_data() amended
Fixes few mistypes and compilation warning:
```
sssd-2.2.3/src/providers/ipa/ipa_s2n_exop.c:665:20: warning: 'gc' may be used uninitialized in this function [-Wmaybe-uninitialized]
attrs->ngroups = gc;
~~~~~~~~~~~~~~~^~~~
```
Related to https://pagure.io/SSSD/sssd/issue/4078
Reviewed-by: Sumit Bose <sbose@redhat.com>