[REF] .travis.yml: Using shortcut to install phantomjs 2, ruby 2 and compass

Ruby 2 fix https://github.com/Compass/compass/issues/1513#issuecomment-32276852
Phantomjs 2 fix `odoo.tests.common: phantomjs: u"ReferenceError: Can't find variable: MutationObserver`

.travis.yml

@@ -15,6 +15,7 @@ addons:
 env:
   global:
   - VERSION="10.0" TESTS="0" LINT_CHECK="0" TRANSIFEX="0"
+  - PHANTOMJS_VERSION="2.1.2" WEBSITE_REPO="1"
   - TRANSIFEX_USER='transbot@odoo-community.org'
   - secure: "GRXFURohRzzBbzRovVHd+cObj1yBe9x9bddKqUo7jEGPo+MYHKfGo1M7disTDq6HPLgCwacbhWRsMavGORB3AEkoNewP7q31MKGGPiS8Com9wMmYUtDPs4ZiuUlakJjvfsmGlpwTWUe1Xv1YSZweXVGIESAn0SwhzKHrSKiTcSFAapTwdZXt0lKIsDcra/xOesJ8p9QjY4mzsgyeLrLUSq/Gpt/icAJeoktJ2c4Z6sMV4ozbaRgMFSMCxXKXQTNtLgFICfiJZ2PAw3BQTYo6iX0sdX3RekvaWVBiFr1iblrFjZleoZ9CnkOEKq0JL8EXHMeX7UBvkSJvQV4M3DPd5GdHA0docKDwgdJKUSP9oxBJ6ElYxG5/bbwOxWfY0x6mh/iJdSuNyrfaUqzaCfhQsckuEw6IgqcMGWLPoO5FSovzAtC+u0+GIqphyFsA25lku9B76eZB8KuqWEUJGQZswIOYUKc0i1A2S/ej6MjCYW0BrazhN5laP/6nu7RHmYs0sIrIaxeJJZG0AaVKWAXmTbcDplF07wzwQau4nk922pH5Bxmt2hB1BOzeOqCGnE3wTOAuacuDIfyJaIpTmNMALWeWk/EkMghDZXRRCEueZO5QR2LdcxJk86x5ANj6sxKVo+nkl+x93ZBsehqELn4rTHwjAaA+Ck3vWRkzfV8nJ3A="
   matrix:
@@ -26,11 +27,6 @@ env:
 virtualenv:
   system_site_packages: true
 
-before_install:
-  - rvm install ruby --latest
-  - rvm use ruby --latest
-  - gem install compass bootstrap-sass
-
 install:
   - git clone --depth=1 https://github.com/OCA/maintainer-quality-tools.git ${HOME}/maintainer-quality-tools
   - export PATH=${HOME}/maintainer-quality-tools/travis:${PATH}