Ticket 47427 - Overflow in nsslapd-disk-monitoring-threshold
    
    Bug Description:  If you directory try and set the threshold to -2,
                      the server allows it, but it should be rejected.
    
    Fix Description:  With PR_snprintf and other NSPR formatting functions,
                      %lld must be used with LONG_MAX, instead of %ld which
                      must be used with regular printf.
    
    https://fedorahosted.org/389/ticket/47427
    
    Reviewed by: mreynolds (Thanks!)