travis: use groonga setup script

.travis.yml

@@ -2,7 +2,4 @@ language: node_js
 node_js:
  - 0.6
 before_install:
- - echo "deb http://packages.groonga.org/ubuntu/ $(lsb_release --short --codename) universe" | sudo tee /etc/apt/sources.list.d/groonga.list
- - sudo apt-get update
- - sudo apt-get -y --allow-unauthenticated install groonga-keyring
- - sudo apt-get -y --force-yes install libgroonga-dev
+ - curl https://raw.github.com/groonga/groonga/master/data/travis/setup.sh | sh