ipa-cert-fix: handle 'pki-server cert-fix' failure
When DS cert is expired, 'pki-server cert-fix' will fail at the
final step (restart). When this case arises, ignore the
CalledProcessError and continue.
We can't know for sure if the error was due to failure of final
restart, or something going wrong earlier. But if it was a more
serious failure, the next step (installing the renewed IPA-specific
certificates) will fail.
Part of: https://pagure.io/freeipa/issue/7885
Reviewed-By: Florence Blanc-Renaud <flo@redhat.com>