fix travis build

Author: feross

.travis.yml

@@ -8,4 +8,3 @@ before_script:
   - if [ "${TRAVIS_OS_NAME}" == "linux" ]; then
       sudo sh -c 'echo 0 > /proc/sys/net/ipv6/conf/all/disable_ipv6';
     fi
-  - export DISPLAY=:99.0; sh -e /etc/init.d/xvfb start