Fix a crash when calling 'validateaddress' with no wallet.
Fix a crash when calling 'validateaddress' with no wallet.

nlgcoin/guldencoin-official,nlgcoin/guldencoin-official,nlgcoin/guldencoin-official,nlgcoin/guldencoin-official,nlgcoin/guldencoin-official,nlgcoin/guldencoin-official