Remove `existing` from PATH when adding `Gem.bindir`.
Remove `existing` from PATH when adding `Gem.bindir`.

gregory-nisbet/brew,muellermartin/dist,maxim-belkin/brew,amar-laksh/brew_sudo,claui/brew,DomT4/brew,hanxue/linuxbrew,alyssais/brew,hanxue/linuxbrew,EricFromCanada/brew,mahori/brew,nandub/brew,vitorgalvao/brew,jmsundar/brew,sjackman/homebrew,reelsense/brew,EricFromCanada/brew,EricFromCanada/brew,ilovezfs/brew,bfontaine/brew,alyssais/brew,mahori/brew,pseudocody/brew,zmwangx/brew,JCount/brew,MikeMcQuaid/brew,amar-laksh/brew_sudo,gregory-nisbet/brew,bfontaine/brew,sjackman/homebrew,nandub/brew,zmwangx/brew,reitermarkus/brew,mahori/brew,rwhogg/brew,jmsundar/brew,konqui/brew,Homebrew/brew,konqui/brew,reitermarkus/brew,claui/brew,claui/brew,aw1621107/brew,konqui/brew,mgrimes/brew,Homebrew/brew,MikeMcQuaid/brew,ilovezfs/brew,mgrimes/brew,JCount/brew,Linuxbrew/brew,zmwangx/brew,tonyg/homebrew,MikeMcQuaid/brew,reelsense/brew,palxex/brew,DomT4/brew,DomT4/brew,claui/brew,pseudocody/brew,bfontaine/brew,hanxue/linuxbrew,jmsundar/brew,EricFromCanada/brew,nandub/brew,muellermartin/dist,JCount/brew,maxim-belkin/brew,tonyg/homebrew,reitermarkus/brew,Linuxbrew/brew,mahori/brew,aw1621107/brew,JCount/brew,aw1621107/brew,gregory-nisbet/brew,Linuxbrew/brew,palxex/brew,Homebrew/brew,sjackman/homebrew,rwhogg/brew,Linuxbrew/brew,MikeMcQuaid/brew,pseudocody/brew,vitorgalvao/brew,palxex/brew,vitorgalvao/brew,Homebrew/brew,konqui/brew,rwhogg/brew,sjackman/homebrew,mgrimes/brew,reitermarkus/brew,alyssais/brew,vitorgalvao/brew,reelsense/brew,DomT4/brew,amar-laksh/brew_sudo,nandub/brew,muellermartin/dist,ilovezfs/brew,maxim-belkin/brew,tonyg/homebrew