Ticket 47810 - investigate betxn plugins to ensure they
     return the correct error code
    
    Bug Description:  Prior to backend transaction plugin types, postop error
                      codes didn't really have an effect, so often times a success
                      result was implicitly being returned.
    
    Fix Description:  Alawys return the correct error code for all backend transaction
                      plugins.
    
    https://fedorahosted.org/389/ticket/47810
    
    Jenkins: Passed
    TET: Passed
    
    Reviewed by: nhosoi(Thanks!)