travis.yml: tweak how we handle homebrew/test-bot.
travis.yml: tweak how we handle homebrew/test-bot.

On Linux this is currently blowing up for our tags so let's change the
approach.

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