Ticket #47874 - Performance degradation with scope ONE after some load
    
    Bug Description: Backend has a bit to indicate "should not bypass
    the filter test".  It's set if one of the search results is ALLID
    in idl_intersection.  Once the flag is set, it's never been unset.
    It makes the following one level searches slow down.
    
    Fix Description: Introduced slapi_be_unset_flag and unset the bit
    at the end of every search.
    
    https://fedorahosted.org/389/ticket/47874
    
    Reviewed by rmeggins@redhat.com (Thank you, Rich!!)