Use the newer stack for HHVM on Tracis CI
Use the newer stack for HHVM on Tracis CI

yodur2potassium/test-behat-selenium-symfo,voronkovich/symfony-demo,bocharsky-bw/symfony-demo,dzuelke/symfony-demo,yceruto/symfony-demo,symfony/symfony-demo,yodur2potassium/test-behat-selenium-symfo,symfony/symfony-demo,dzuelke/symfony-demo,javiereguiluz/symfony-demo,voronkovich/symfony-demo,dzuelke/symfony-demo,voronkovich/symfony-demo,bocharsky-bw/symfony-demo,TomasVotruba/symfony-demo,Codeception/symfony-demo,Codeception/symfony-demo,symfony/symfony-demo,yceruto/symfony-demo,javiereguiluz/symfony-demo,bocharsky-bw/symfony-demo,yodur2potassium/test-behat-selenium-symfo,TomasVotruba/symfony-demo,javiereguiluz/symfony-demo,Codeception/symfony-demo,yceruto/symfony-demo,TomasVotruba/symfony-demo