gcc already newer version since using trusty now and not precise

.travis.yml

@@ -3,13 +3,11 @@ sudo: required
 
 env:
   TRAVIS_DOCKER_COMPOSE_VERSION: 1.12.0
-  TRAVIS_GCC_VERSION: 4.9
   TRAVIS_NODE_VERSION: 4.8.1
   TRAVIS_NPM_VERSION: 4.4.4
 
 before_install:
   - sudo apt-get update -y
-  - sudo apt-get install -y gcc-${TRAVIS_GCC_VERSION}
   - npm install -g npm@${TRAVIS_NPM_VERSION}
   - sudo curl -fsSL https://get.docker.com/ | sh
   - if [ -e /usr/local/bin/docker-compose ]; then sudo rm /usr/local/bin/docker-compose; fi