dnssec: keep dnssec daemons in Python2
Until DNSSEC is ready for Python3, we should run DNSSEC with Python 2.
Related: https://pagure.io/freeipa/issue/4985
Signed-off-by: Tomas Krizek <tkrizek@redhat.com>
Reviewed-By: Stanislav Laznicka <slaznick@redhat.com>