Don't allow hhvm to fail in travis

Author: raulfraile

.travis.yml

@@ -7,10 +7,6 @@ php:
   - hhvm
   - 7.0
 
-matrix:
-  allow_failures:
-    - php: hhvm
-
 before_script:
   - sudo apt-get update -qq
   - sudo apt-get install -y unzip
@@ -21,6 +17,7 @@ before_script:
   - sh -c 'if [ "$TRAVIS_PHP_VERSION" != "hhvm" ]; then pecl install zip; fi;'
   - sh -c 'if [ "$TRAVIS_PHP_VERSION" != "hhvm" ]; then pecl install rar; fi;'
   - sh -c 'if [ "$TRAVIS_PHP_VERSION" = "hhvm" ]; then echo "phar.readonly = 0" > travis.hhvm.ini; fi;'
+  - /home/travis/.phpenv/versions/$(phpenv version-name)/bin/composer self-update
   - composer install --prefer-source
 
 script: