edit .gitlabci file

1 job for gitlab in 1 minute and 11 seconds (queued for 3 seconds)
Status Job ID Name Coverage
  Test
failed #2949545
jobs

00:01:11

 
Name Stage Failure
failed
jobs Test There is an unknown failure, please try again

2016-08-09 14:51:15 (20.8 MB/s) - ‘arduino-1.6.9-linux64.tar.xz’ saved [96075820/96075820]

$ tar xf arduino-1.6.9-linux64.tar.xz
$ export DISPLAY=:1.0
$ /sbin/start-stop-daemon --start --quiet --pidfile /tmp/xvfb_1.pid --make-pidfile --background --exec /usr/bin/Xvfb -- :1 -ac -screen 0 1280x1024x16
/sbin/start-stop-daemon: unable to stat /usr/bin/Xvfb (No such file or directory)

ERROR: Build failed: exit code 1