uses: allow checking deleted formulae.
uses: allow checking deleted formulae.

This is useful for seeing when formulae are deleted if they are going to
leave behind any formulae that depend on them.

As a result, if there are any formulae returned return a non-zero/failed
exit status.

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