Ticket 47427 - Overflow in nsslapd-disk-monitoring-threshold
    
    Bug Description:  Using ldapsearch shows threshold value as a negative number, even
                      though the feature is working correctly.
    
    Fix Description:  When reading the dse, the server was trying to cast the value as a "int".
                      Changed CONFIG_INT to CONFIG_LONG for nsslapd-disk-monioring-threshold.
    
    https://fedorahosted.org/389/ticket/47427
    
    Reviewed by: richm(Thanks!)
    (cherry picked from commit 90c04c096876447ed3c1be0356fc346d3e492dc2)