ipa-migrate - do not process AD entgries in staging mode
    
    Only migrate AD entries in production mode due to schema conflicts
    created when removing certain AD attributes (e.g.
    ipantsecurityidentifier)
    
    SIgned-off-by: Mark Reynolds <mreynolds@redhat.com>
    relates: https://pagure.io/freeipa/issue/9776
    Reviewed-By: Rob Crittenden <rcritten@redhat.com>