Ticket 47810 - memberOf plugin not properly rejecting updates
    
    Bug Description:  When the memberOf plugin tries to add memberOf attribute to
                      an entry during a mod-replace on a group, even though the
                      update to the user entry fails, but plugin still allows
                      the member to be added to the group.
    
    Fix Description:  During a mod/replace check and return an error if the member
                      update fails.
    
    https://fedorahosted.org/389/ticket/47810
    
    Reviewed by: nhosoi(Thanks!)
    
    (cherry picked from commit eb54f03e240402a4bd16f9cde1d66539805f56ea)
    
    Conflicts:
    	dirsrvtests/suites/betxns/betxn_test.py