fix(travis): remove explicit call to xvfb

Author: christopherthielen

.travis.yml

@@ -4,7 +4,6 @@ services:
   - xvfb
 before_install:
   - sudo apt-get install libgconf-2-4
-  - sh -e /etc/init.d/xvfb start
   - export PATH=$HOME/.yarn/bin:$PATH
   - curl -o- -L https://yarnpkg.com/install.sh | bash -s -- --version 1.5.1
 script: