With opendnssec 2, read the zone list from file
    
    With OpenDNSSEC 1.4, the code was using the command
    $ ods-ksmutil zonelist export
    which printed the zonelist as XML in its output.
    With OpenDNSSEC 2, the code is using the command
    $ ods-enforcer zonelist export
    which prints a message instead:
    "Exported zonelist to /etc/opendnssec/zonelist.xml successfully"
    The code needs to extract the zonelist file name and read the XML
    from the file.
    
    Related: https://pagure.io/freeipa/issue/8214
    Reviewed-By: Christian Heimes <cheimes@redhat.com>
    Reviewed-By: Alexander Bokovoy <abokovoy@redhat.com>