Synchronize Keg#link and #unlink counts
Synchronize Keg#link and #unlink counts

Keg#link would sometimes count a linked file when doing mkpath, even if
the target directory already exists; #unlink would never count it. This
meant that "brew ln" and "brew unlink" counts for the same keg could be
out of sync with each other.

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