GitDownloadStrategy: reset after checkout during updates
GitDownloadStrategy: reset after checkout during updates

Otherwise, if the local branch is behind the remote branch, or has
diverged, we will stage the wrong revision.

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