Ticket #47571 - targetattr ACIs ignore subtype
    
    Description: commit 85a78741dfeb636a1cf7cced1576278e65f5bb58
    introduced 2 coverity issues:
    12423: Explicit null dereferenced
    do_search (slapd/search.c)
    If attribute list contains multiple "*"s and "aci"s in ldapsearch,
    the previous code attempted to add "aci" once for "*" and replacing
    "aci" with normalized aci (if any) once and eliminating the duplicated
    "aci"s. The code contained a null dereferenced bug. Even if duplicated
    attributes are included in the attribute list, they are removed later
    in send_specific_attrs. Thus, this patch simplifies the logic to avoid
    the null dereference.
    
    12422: Logically dead code
    comp_cmp (slapd/attr.c)
    Eliminated the dead code (case s1 == NULL AND s2 == NULL).
    
    https://fedorahosted.org/389/ticket/47571
    
    Reviewed by rmeggins@redhat.com (Thank you, Rich!!)
    (cherry picked from commit 36c48b8395c6e4ca374c74f91dad6b022aa99ce1)