.travis.yml: Add HOMEBREW_NO_AUTO_UPDATE=1
.travis.yml: Add HOMEBREW_NO_AUTO_UPDATE=1

Fix error: Checking for Homebrew updates...
fatal: empty ident name not allowed

parcollet/homebrew-science,pditommaso/homebrew-science,dpo/homebrew-science,maplesond/homebrew-science,philippbayer/homebrew-science,heuermh/homebrew-science,DabeDotCom/homebrew-science,andrewjpage/homebrew-science,quantumsteve/homebrew-science,kozo2/homebrew-science