Ticket 47817 - The error result text message should be obtained just prior to sending result
    
    Bug Description:  We do not get pblock result message after the betxn postop plugins
                      are called.  If a betxn plugin modified the ldap result message, then
                      when the backend returns the results it does an invalid read on the
                      old pointer of the old result message.
    
    Fix Description:  Get the result message after we call the betxn postop plugins.
    
    https://fedorahosted.org/389/ticket/47817
    
    jenkins: passed
    
    Reviewed by: nhosoi(Thanks!)
    
    (cherry picked from commit 68e766891d1067b2b86bd48bfa16d0837fa5a737)