brew.rb: handle cask autoinstall when cask tapped.
brew.rb: handle cask autoinstall when cask tapped.

Otherwise it would assume if `cask` was tapped it was also installed.

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