[SSSD] [sssd PR#923][opened] PRNG usage amended

[alexey-tikhonov]

URL: https://github.com/SSSD/sssd/pull/923
Author: alexey-tikhonov
 Title: #923: PRNG usage amended
Action: opened

PR body:
"""
This PR is intended to address https://pagure.io/SSSD/sssd/issue/4024#comment-603526

sss_rand() was:
     - moved out of crypto lib,
     - non security relevant purpose was emphasized
     - attempt to "use RAND_bytes() if available" was removed to simplify
       things and make return value compatible with rand()

MMAP_CACHE: use CSPRNG to init hash table seed

"""

To pull the PR as Git branch:
git remote add ghsssd https://github.com/SSSD/sssd
git fetch ghsssd pull/923/head:pr923
git checkout pr923