Update .travis.yml
Update .travis.yml

- make TCMALLOC explicit
c-cube/lean,leodemoura/lean,codyroux/lean0.1,c-cube/lean,fpvandoorn/lean2,fpvandoorn/lean,rlewis1988/lean,UlrikBuchholtz/lean,digama0/lean,rlewis1988/lean,soonhokong/travis_test,eigengrau/lean,soonhokong/lean-windows,c-cube/lean,javra/lean,leodemoura/lean,codyroux/lean0.1,fgdorais/lean,leanprover-community/lean,avigad/lean,soonhokong/travis_test,UlrikBuchholtz/lean,soonhokong/lean,dselsam/lean,Kha/lean,dselsam/lean,leanprover/lean,Kha/lean,eigengrau/lean,leanprover-community/lean,levnach/lean,digama0/lean,UlrikBuchholtz/lean,soonhokong/lean-windows,htzh/lean,fpvandoorn/lean,sp3ctum/lean,codyroux/lean0.1,johoelzl/lean,eigengrau/lean,Kha/lean,leodemoura/lean,leodemoura/lean,leanprover/lean,soonhokong/lean-osx,c-cube/lean,digama0/lean,eigengrau/lean,javra/lean,fpvandoorn/lean2,sp3ctum/lean,sp3ctum/lean,fgdorais/lean,soonhokong/travis_test,soonhokong/lean-osx,leanprover/lean,fpvandoorn/lean2,UlrikBuchholtz/lean,soonhokong/lean-windows,avigad/lean,levnach/lean,dselsam/lean,javra/lean,rlewis1988/lean,johoelzl/lean,johoelzl/lean,c-cube/lean,htzh/lean,rlewis1988/lean,javra/lean,johoelzl/lean,avigad/lean,soonhokong/lean-windows,levnach/lean,avigad/lean,javra/lean,soonhokong/lean-osx,fgdorais/lean,soonhokong/lean,fpvandoorn/lean2,fpvandoorn/lean,rlewis1988/lean,htzh/lean,eigengrau/lean,dselsam/lean,johoelzl/lean,soonhokong/lean,Kha/lean,codyroux/lean0.1,soonhokong/travis_test,johoelzl/lean,fgdorais/lean,digama0/lean,htzh/lean,digama0/lean,rlewis1988/lean,levnach/lean,soonhokong/lean-windows,leanprover/lean,fpvandoorn/lean,soonhokong/lean,sp3ctum/lean,leodemoura/lean,fgdorais/lean,fpvandoorn/lean,fpvandoorn/lean2,leanprover-community/lean,soonhokong/lean-osx,leodemoura/lean,dselsam/lean,leanprover/lean,digama0/lean,levnach/lean,leanprover-community/lean,leanprover-community/lean,Kha/lean,UlrikBuchholtz/lean,htzh/lean,leanprover/lean,sp3ctum/lean,avigad/lean,dselsam/lean,fpvandoorn/lean,soonhokong/lean,avigad/lean,leanprover-community/lean,Kha/lean,soonhokong/lean-osx,fgdorais/lean