bin/bash: don't require executable command files
bin/bash: don't require executable command files

Commands implemented in shell (bash) are supposed to be sourced from
`bin/bash` instead of being executed directly. Consequently, don't
expect the implementation files to be executable.

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