Minor improvement in .travis.yml to make builds faster
Minor improvement in .travis.yml to make builds faster

samuelralak/ForkHub,mishin/ForkHub,DeLaSalleUniversity-Manila/forkhub-JJCpro10,mishin/ForkHub,arcivanov/ForkHub,DeLaSalleUniversity-Manila/forkhub-JJCpro10,DeLaSalleUniversity-Manila/forkhub-JJCpro10,samuelralak/ForkHub,ywk248248/Forkhub_cloned,xfumihiro/ForkHub,jonan/ForkHub,jonan/ForkHub,arcivanov/ForkHub,ywk248248/Forkhub_cloned,ywk248248/Forkhub_cloned,jonan/ForkHub,mishin/ForkHub,xfumihiro/ForkHub,arcivanov/ForkHub,samuelralak/ForkHub,xfumihiro/ForkHub