fix #1523: prevent side-effect of _format_request
fix #1523: prevent side-effect of _format_request

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