Title: #246: filter_users and filter_groups stop working properly in v 1.15
What do we want to do in this case? It would fail with EINVAL later
on when filling the grent/pwent anyways, no?
That comment should said `ENOMEM`. If `name` is `NULL`, `sss_output_name` will return
`NULL` and we fail with `ENOMEM`.
And last comment ... the introduced functions are not dealing with
cache_req_result at all. What they do is changing the ldb_result and moving this part of
the code to the cache_req_result.c does seem a little bit weird to me.
But it still deals in some sort of result that is used but cache_req` so I think it is ok.
It deserves to be placed in separate function at least, doesn't matter if static or in
See the full comment at https://github.com/SSSD/sssd/pull/246#issuecomment-297654116