Install "sass" and "compass" as gems to get recent versions.

.travis.yml

@@ -7,11 +7,16 @@ go:
   - 1.2
   - tip
 
+env:
+  - GEM_HOME=/var/lib/gems/1.8
+
 before_install:
   - sudo apt-get update
 
 install:
-  - sudo apt-get -y install nodejs npm ruby-sass ruby-compass python-babel
+  - sudo apt-get -y install nodejs npm rubygems python-babel
+  - sudo gem install sass
+  - sudo gem install compass
     # 'npm config set ca ""' required only for node 0.6
     # which is installed on Travis CI
     # see https://github.com/npm/npm/issues/4379#issuecomment-31590254