[SSSD] [sssd PR#211][opened] IFP: Fix of limit = 0 (unlimited result)

[celestian]

URL: https://github.com/SSSD/sssd/pull/211
Author: celestian
 Title: #211: IFP: Fix of limit = 0 (unlimited result)
Action: opened

PR body:
"""
If we set limit to 0 it means that result is unlimited. Internally we
restrict number of result by allocation of result array.
In unlimited case there was a bug and zero array was allocated.
This fix allocates neccessary array when we know real result size.

Resolves:
https://pagure.io/SSSD/sssd/issue/3306

How to test (this reproducer needs #208 "IFP: Filter with * in Users.ListByName method" applied)
```
systemctl daemon-reload
sudo su -c "truncate -s0 /var/log/sssd/*.log"
sudo su -c "rm -f /var/lib/sss/db/*" 
sudo su -c "rm -f /var/lib/sss/mc/*"
sudo systemctl restart sssd.service

sudo su -c "truncate -s0 /var/log/sssd/*.log"

dbus-send --system --print-reply  --dest=org.freedesktop.sssd.infopipe \
    /org/freedesktop/sssd/infopipe/Users \
    org.freedesktop.sssd.infopipe.Users.ListByName \
    string:"*" uint32:"0"

dbus-send --system --print-reply  --dest=org.freedesktop.sssd.infopipe \
    /org/freedesktop/sssd/infopipe/Groups \
    org.freedesktop.sssd.infopipe.Groups.ListByName \
    string:"*" uint32:"100"

dbus-send --system --print-reply  --dest=org.freedesktop.sssd.infopipe \
    /org/freedesktop/sssd/infopipe/Users \
    org.freedesktop.sssd.infopipe.Users.ListByDomainAndName \
    string:"domain.cygnus" string:"*" uint32:"100"
```
"""

To pull the PR as Git branch:
git remote add ghsssd https://github.com/SSSD/sssd
git fetch ghsssd pull/211/head:pr211
git checkout pr211