Remove magic sleep from create_index_task
    
    11 years ago 5ad91a0781 added a magic sleep to work around a rare deadlock
    bug in memberOf plugin. Thierry is not aware of any outstanding issues
    with memberOf plugin that could lead to a deadlock.
    
    Related: https://pagure.io/freeipa/issue/8521
    Signed-off-by: Christian Heimes <cheimes@redhat.com>
    Reviewed-By: Rob Crittenden <rcritten@redhat.com>