Ticket 47740 - Fix coverity issues: null deferences - Part 6
    
    12474 - Null pointer dereference - ldap/servers/slapd/tools/migratecred.c
    12473 - Null pointer dereference - ldap/srevers/slapd/snmp/main.c
    12468 - Null pointer dereference - ldap/servers/plugins/memberof/memberof.c
    
    https://fedorahosted.org/389/ticket/47740
    
    Reviewed by: rmeggins(Thanks!)