Don't remove linked formulas when doing a 'cleanup'
Don't remove linked formulas when doing a 'cleanup'

Closes Homebrew/homebrew#16947.

Signed-off-by: Adam Vandenberg <34c2b6407fd5a10249a15d699d40f9ed1782e98c@gmail.com>

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