travis.yml: Bump clang to 3.9
travis.yml: Bump clang to 3.9

Somasis/kakoune,Somasis/kakoune,danr/kakoune,jjthrash/kakoune,danr/kakoune,jkonecny12/kakoune,jjthrash/kakoune,mawww/kakoune,jkonecny12/kakoune,Somasis/kakoune,alexherbo2/kakoune,jkonecny12/kakoune,mawww/kakoune,occivink/kakoune,casimir/kakoune,casimir/kakoune,jkonecny12/kakoune,alexherbo2/kakoune,lenormf/kakoune,lenormf/kakoune,lenormf/kakoune,casimir/kakoune,mawww/kakoune,danr/kakoune,casimir/kakoune,jjthrash/kakoune,alexherbo2/kakoune,lenormf/kakoune,danr/kakoune,mawww/kakoune,occivink/kakoune,Somasis/kakoune,occivink/kakoune,occivink/kakoune,jjthrash/kakoune,alexherbo2/kakoune