fix #2204
fix #2204

avoid exception in close_interface when interface.server is not in
self.interfaces

pooler/electrum-ltc,fujicoin/electrum-fjc,spesmilo/electrum,digitalbitbox/electrum,vialectrum/vialectrum,fireduck64/electrum,dashpay/electrum-dash,argentumproject/electrum-arg,pooler/electrum-ltc,fireduck64/electrum,vertcoin/electrum-vtc,neocogent/electrum,kyuupichan/electrum,dashpay/electrum-dash,neocogent/electrum,vertcoin/electrum-vtc,pknight007/electrum-vtc,kyuupichan/electrum,romanz/electrum,fireduck64/electrum,asfin/electrum,molecular/electrum,vialectrum/vialectrum,argentumproject/electrum-arg,wakiyamap/electrum-mona,wakiyamap/electrum-mona,fyookball/electrum,digitalbitbox/electrum,vialectrum/vialectrum,argentumproject/electrum-arg,digitalbitbox/electrum,fireduck64/electrum,dabura667/electrum,pooler/electrum-ltc,cryptapus/electrum,cryptapus/electrum,argentumproject/electrum-arg,dashpay/electrum-dash,cryptapus/electrum,romanz/electrum,pknight007/electrum-vtc,neocogent/electrum,molecular/electrum,asfin/electrum,dashpay/electrum-dash,fujicoin/electrum-fjc,vertcoin/electrum-vtc,pooler/electrum-ltc,romanz/electrum,pknight007/electrum-vtc,fyookball/electrum,pknight007/electrum-vtc,fujicoin/electrum-fjc,asfin/electrum,wakiyamap/electrum-mona,dabura667/electrum,dabura667/electrum,spesmilo/electrum,vertcoin/electrum-vtc,spesmilo/electrum,kyuupichan/electrum,digitalbitbox/electrum,molecular/electrum,spesmilo/electrum,dabura667/electrum,molecular/electrum,fyookball/electrum,wakiyamap/electrum-mona