Added a proper workaround for dnssec test failures in Beaker environment
    
    In beaker lab the situation when master and replica have ip addresses from
    different subnets is quite frequent. When a replica has ip from different
    subnet than master's, ipa-replica-prepare looks up a proper reverse zone to
    add a pointer record, and if it does not find it, it asks a user for permission
    to create it automatically. It breaks the tests adding the unexpected input.
    The workaround is to always create a reverse zone for a new replica.
    
    Corresponding ticket is https://fedorahosted.org/freeipa/ticket/5306
    
    Reviewed-By: Petr Spacek <pspacek@redhat.com>
    Reviewed-By: Martin Basti <mbasti@redhat.com>