[SSSD] [sssd PR#690][opened] DYNDNS: Convert dyndns timer to be_ptask

[thalman]

   URL: https://github.com/SSSD/sssd/pull/690
Author: thalman
 Title: #690: DYNDNS: Convert dyndns timer to be_ptask
Action: opened

PR body:
"""
We have API for periodic tasks and we want to
use it instead of tevent timers.

Resolves:
https://pagure.io/SSSD/sssd/issue/1944
"""

To pull the PR as Git branch:
git remote add ghsssd https://github.com/SSSD/sssd
git fetch ghsssd pull/690/head:pr690
git checkout pr690