Check if nud actually controls custodian address

[Desrever Nu]

as suggested by mos

nud -unit=B validateaddress BBZ4h88BwYCyE9q268LoArps6eodq9PDGH
{
    "isvalid" : true,
    "address" : "BBZ4h88BwYCyE9q268LoArps6eodq9PDGH",
    "ismine" : false
}