Install xvfb in travis container.

.travis.yml

@@ -5,19 +5,16 @@ node_js:
 services:
 - docker
 - ntp
+- xvfb
 addons:
   chrome: stable
   apt:
     sources:
     - google-chrome
     packages:
+    - xvfb
     - libgif-dev
     - google-chrome-stable
-
-before_script:
-- export DISPLAY=:99.0
-- sh -e /etc/init.d/xvfb start
-- sleep 3
 script:
 - "./scripts/authelia-scripts travis"
 after_success: