brew.sh: change directory for HOMEBREW_VERSION.
brew.sh: change directory for HOMEBREW_VERSION.

This stops `-dirty` showing up whenever you aren't in
`HOMEBREW_REPOSITORY`.

Fixes #1108.

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