ipa-backup: restart services before compressing the backup
ipa-backup gathers all the files needed for the backup, then compresses
the file and finally restarts the IPA services. When the backup is a
large file, the compression may take time and widen the unavailabity
window.
This fix restarts the services as soon as all the required files are
gathered, and compresses after services are restarted.
Fixes: https://pagure.io/freeipa/issue/7632
Reviewed-By: Rob Crittenden <rcritten@redhat.com>