Add ARGV.build_head? and use it.
Add ARGV.build_head? and use it.

This allows both "--HEAD" and "-H" to be used consistently, which was the
intention in the first place.

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