minor #171 Updated Travis CI configuration (javiereguiluz)
minor #171 Updated Travis CI configuration (javiereguiluz)

This PR was squashed before being merged into the master branch (closes #171).

Discussion
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Updated Travis CI configuration

Changes made as recommended by @stof in https://github.com/symfony/symfony-demo/pull/154#issuecomment-137465466

Commits
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67eb585 Updated Travis CI configuration

AntoineToubhans/symfony-demo,healthefrog/symfony-demo,symfony/symfony-demo,vakstk50/jenkinstest,loicgelle/symfony-demo,AntoineToubhans/symfony-demo,TomasVotruba/symfony-demo,theofidry/AliceBundleBenchmarking,jzawadzki/symfony-demo,ReLexEd/symfony-demo,taueres/symfony-demo,mrook/symfony-behat-codeception-demo,xabbuh/symfony-demo,mrook/symfony-behat-codeception-demo,GregSatre/symfony-demo,GregSatre/symfony-demo,nilamkhedkar1/symfony_demo,tekjava/symfony-demo,voronkovich/symfony-demo,Codeception/symfony-demo,bocharsky-bw/symfony-demo,nilamkhedkar1/symfony_demo,loicgelle/symfony-demo,dkownacki/symfony_demo,yceruto/symfony-demo,dkownacki/symfony_demo,gliderShip/symfony_demo,dzuelke/symfony-demo,GregSatre/symfony-demo,yodur2potassium/test-behat-selenium-symfo,maidmaid/symfony-demo,michalmrzyk/symfony-demo,dzuelke/symfony-demo,yceruto/symfony-demo,rasanga/symfony-demo,tekjava/symfony-demo,voronkovich/symfony-demo,rasanga/symfony-demo,yceruto/symfony-demo,taueres/symfony-demo,TomasVotruba/symfony-demo,Codeception/symfony-demo,javiereguiluz/symfony-demo,bocharsky-bw/symfony-demo,maidmaid/symfony-demo,dkownacki/symfony_demo,taueres/symfony-demo,xabbuh/symfony-demo,AntoineToubhans/symfony-demo,cristi-contiu/symfony-demo,symfony/symfony-demo,GregSatre/symfony-demo,voronkovich/symfony-demo,tekjava/symfony-demo,xabbuh/symfony-demo,michalmrzyk/symfony-demo,vakstk50/jenkinstest,healthefrog/symfony-demo,vakstk50/jenkinstest,AntoineToubhans/symfony-demo,Samox/symfony-demo,healthefrog/symfony-demo,cristi-contiu/symfony-demo,maidmaid/symfony-demo,samitiana/symfony-demo,jzawadzki/symfony-demo,mrook/symfony-behat-codeception-demo,symfony/symfony-demo,nilamkhedkar1/symfony_demo,TomasVotruba/symfony-demo,michalmrzyk/symfony-demo,Codeception/symfony-demo,cristi-contiu/symfony-demo,ReLexEd/symfony-demo,Samox/symfony-demo,javiereguiluz/symfony-demo,loicgelle/symfony-demo,bocharsky-bw/symfony-demo,Samox/symfony-demo,Samox/symfony-demo,rasanga/symfony-demo,samitiana/symfony-demo,dzuelke/symfony-demo,yodur2potassium/test-behat-selenium-symfo,samitiana/symfony-demo,javiereguiluz/symfony-demo,taueres/symfony-demo,gliderShip/symfony_demo,theofidry/AliceBundleBenchmarking,ReLexEd/symfony-demo,theofidry/AliceBundleBenchmarking,yodur2potassium/test-behat-selenium-symfo,jzawadzki/symfony-demo,gliderShip/symfony_demo