Merge pull request #368 from FriendsOfSymfony/hhvm-build

fix hhvm build on travis

Author: dbu

.travis.yml

@@ -17,7 +17,6 @@ php:
   - 5.6
   - 7.0
   - 7.1
-  - hhvm
 
 env:
   - SYMFONY_VERSION='3.1.*'
@@ -47,6 +46,9 @@ matrix:
     - php: 7.1
       env:
         - SYMFONY_VERSION='3.2.*'
+    - php: hhvm
+      dist: trusty
+
 install:
   - pip install -qr Resources/doc/requirements.txt --user