ipatests: expect SOA serial option deprecation warning
    
    Tests must be updated to expect the new deprecation warning.
    
    Related: https://pagure.io/freeipa/issue/8227
    Signed-off-by: Antonio Torres <antorres@redhat.com>
    Reviewed-By: François Cami <fcami@redhat.com>
    Reviewed-By: Rob Crittenden <rcritten@redhat.com>
    Reviewed-By: Rafael Jeffman <rjeffman@redhat.com>