Ticket 47982 - Fix log hr timestamps when invalid value is set in cn=config
    
    Bug Description:  If an invalid (on / off) value was set, it would leave
    the config as "on", but then turn off logging anyway.
    
    Fix Description:  Check the return code of config_set_onoff, to determine if we
    need to make the logging change.
    
    https://fedorahosted.org/389/ticket/47982
    
    Author: wibrown
    
    Review by: mreynolds (thanks!)