fix can_sign: detect if OldWallet is used
fix can_sign: detect if OldWallet is used

pknight007/electrum-vtc,kyuupichan/electrum,cryptapus/electrum,digitalbitbox/electrum,aasiutin/electrum,procrasti/electrum,fireduck64/electrum,vertcoin/electrum-vtc,dabura667/electrum,digitalbitbox/electrum,pknight007/electrum-vtc,neocogent/electrum,fujicoin/electrum-fjc,pknight007/electrum-vtc,cryptapus/electrum,wakiyamap/electrum-mona,protonn/Electrum-Cash,kyuupichan/electrum,vertcoin/electrum-vtc,cryptapus/electrum-myr,spesmilo/electrum,fyookball/electrum,wakiyamap/electrum-mona,spesmilo/electrum,spesmilo/electrum,pooler/electrum-ltc,cryptapus/electrum-uno,vialectrum/vialectrum,dashpay/electrum-dash,fyookball/electrum,cryptapus/electrum-uno,pooler/electrum-ltc,asfin/electrum,wakiyamap/electrum-mona,argentumproject/electrum-arg,imrehg/electrum,vialectrum/vialectrum,molecular/electrum,lbryio/lbryum,FairCoinTeam/electrum-fair,molecular/electrum,protonn/Electrum-Cash,aasiutin/electrum,argentumproject/electrum-arg,pknight007/electrum-vtc,fyookball/electrum,molecular/electrum,protonn/Electrum-Cash,dashpay/electrum-dash,FairCoinTeam/electrum-fair,romanz/electrum,digitalbitbox/electrum,dabura667/electrum,romanz/electrum,neocogent/electrum,dabura667/electrum,cryptapus/electrum-uno,vertcoin/electrum-vtc,cryptapus/electrum-myr,cryptapus/electrum-myr,cryptapus/electrum-myr,vertcoin/electrum-vtc,aasiutin/electrum,romanz/electrum,fireduck64/electrum,wakiyamap/electrum-mona,pooler/electrum-ltc,procrasti/electrum,molecular/electrum,lbryio/lbryum,imrehg/electrum,spesmilo/electrum,vialectrum/vialectrum,cryptapus/electrum,dashpay/electrum-dash,fireduck64/electrum,dashpay/electrum-dash,argentumproject/electrum-arg,neocogent/electrum,fujicoin/electrum-fjc,asfin/electrum,digitalbitbox/electrum,imrehg/electrum,imrehg/electrum,protonn/Electrum-Cash,fireduck64/electrum,procrasti/electrum,argentumproject/electrum-arg,pooler/electrum-ltc,cryptapus/electrum-uno,procrasti/electrum,asfin/electrum,fujicoin/electrum-fjc,FairCoinTeam/electrum-fair,dabura667/electrum,aasiutin/electrum,kyuupichan/electrum,FairCoinTeam/electrum-fair