[SSSD] [PATCH] LDAP: Fix crash when processing nested groups

[Jakub Hrozek]

https://fedorahosted.org/sssd/ticket/1932

There is a rather strange workaround in the nested groups processing
code that calls tevent_req_post outside _send(). However, it broke in
certain situations where the tevent_req_call resulted in req being freed,
which freed state by extension and then the subsequent _post call was a
use-after-free. This patch saves the two variables used outside state so
that it's safe to use them even after the callback.