Trying to fix Travis CI build

Author: giorgiosironi

before_script.sh

@@ -6,5 +6,5 @@ cd ..
 sh -e /etc/init.d/xvfb start
 export DISPLAY=:99.0
 wget http://selenium.googlecode.com/files/selenium-server-standalone-2.15.0.jar
-java -jar selenium-server-standalone-2.15.0.jar #> /dev/null 2>&1 &
-sleep 2
+java -jar selenium-server-standalone-2.15.0.jar & #> /dev/null 2>&1 &
+sleep 30