Ticket #406 - Impossible to rename entry (modrdn) with Attribute Uniqueness plugin enabled
    
    https://fedorahosted.org/389/ticket/406
    Resolves: Ticket #406
    Bug Description: Impossible to rename entry (modrdn) with Attribute Uniqueness plugin enabled
    Reviewed by: mreynolds (Thanks!)
    Branch: master
    Fix Description: Convert attribute uniqueness to use Slapi_DN* instead of
    char *.  Also found that op_shared_search was always freeing the passed
    in SEARCH_TARGET_SDN, so made that conditional.
    Platforms tested: RHEL6 x86_64
    Flag Day: no
    Doc impact: no
    (cherry picked from commit 832a52d81b8ccc89e765c8cd2e3be801a11db0f4)