remove faulty example of how to set per-request proxy
remove faulty example of how to set per-request proxy

Closes #150

hstrowd/faraday,prcongithub/faraday,grosser/faraday,petems/faraday,mehulkar/faraday,spyofchina/faraday,lostisland/faraday,ru-faraon/Faraday-is-an-HTTP-client,AvaelKross/faraday,hrysd/faraday,O-I/faraday,daviswahl/faraday,davoclavo/faraday,luvtechno/faraday,petems/faraday,engineyard/faraday,spyofchina/faraday,apepper/faraday,customink/faraday,grosser/faraday,AvaelKross/faraday,mauricionr/faraday,pvdb/faraday,jhass/faraday,stayhero/faraday,iamjarvo/faraday,jrafanie/faraday,jrafanie/faraday,ngpestelos/faraday,davoclavo/faraday,santiagodoldan/faraday,flower-pot/faraday,luvtechno/faraday,nevans/faraday,iamjarvo/faraday,davidcornu/faraday,hstrowd/faraday,pvdb/faraday,lostisland/faraday,coinbase/faraday,prcongithub/faraday,customink/faraday,zhaoxl/faraday,mauricionr/faraday,ru-faraon/Faraday-is-an-HTTP-client,coinbase/faraday,davidcornu/faraday,flower-pot/faraday,engineyard/faraday,nevans/faraday,zhaoxl/faraday,daviswahl/faraday,jhass/faraday,zanker/faraday,hrysd/faraday,ekampp/faraday,O-I/faraday,stayhero/faraday,ngpestelos/faraday,santiagodoldan/faraday,zanker/faraday,apepper/faraday,ekampp/faraday,mehulkar/faraday,avdi/faraday