Don't accept Formula objects as dep specs
Don't accept Formula objects as dep specs

It was pointed out that this isn't used at all.

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