Update brew.sh: hide printf's stderr in numeric()
Update brew.sh: hide printf's stderr in numeric()

Avoid #6721 and similar confusing messages during version comparison by hiding printf's stderr (printf woks anyway).
claui/brew,JCount/brew,nandub/brew,MikeMcQuaid/brew,reitermarkus/brew,konqui/brew,claui/brew,sjackman/homebrew,nandub/brew,claui/brew,Homebrew/brew,JCount/brew,EricFromCanada/brew,sjackman/homebrew,MikeMcQuaid/brew,nandub/brew,vitorgalvao/brew,vitorgalvao/brew,mahori/brew,vitorgalvao/brew,sjackman/homebrew,reitermarkus/brew,vitorgalvao/brew,Homebrew/brew,MikeMcQuaid/brew,konqui/brew,JCount/brew,konqui/brew,MikeMcQuaid/brew,reitermarkus/brew,Homebrew/brew,konqui/brew,EricFromCanada/brew,mahori/brew,sjackman/homebrew,reitermarkus/brew,EricFromCanada/brew,mahori/brew,Homebrew/brew,EricFromCanada/brew,mahori/brew,nandub/brew,claui/brew,JCount/brew