Ticket 47969 - COS memory leak when rebuilding the cache
    
    Bug Description:  When the COS cache is released, not all of the schema
                      objectclasses are freed.  So every time we rebuild the
                      COS cache we leak memory.
    
    Fix Description:  After we free the schema attributes, the very first
                      attribute still needs to be freed.  It is not freed
                      initially because of the duplicate checking logic, so
                      it is now done after the loop.
    
    https://fedorahosted.org/389/ticket/47969
    
    Reviewed by: nhosoi(Thanks!)