Switch to Travis-CI container infrastucture

This is just a test and may be reverted if the infrastructure doesn't
prove to be stable or usable (since we test with MongoDB 3.x)

.travis.yml

@@ -2,6 +2,8 @@ language: node_js
 node_js:
  - "0.10"
 
+sudo: false
+
 services:
  - mongodb
 
@@ -12,12 +14,14 @@ addons:
  code_climate:
     repo_token: 9c90177b42d39905ca635b1f6226580dab5799f87f172b66bab4e8df77b67a13
 
-before_install:
-  - sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv 7F0CEB10
-  - echo 'deb http://repo.mongodb.org/apt/ubuntu precise/mongodb-org/3.0 multiverse' | sudo tee /etc/apt/sources.list.d/mongodb-org-3.0.list
-  - echo 'deb http://repo.mongodb.org/apt/ubuntu precise/mongodb-org/3.1 multiverse' | sudo tee /etc/apt/sources.list.d/mongodb-org-3.1.list
-  - sudo apt-get update
-  - sudo apt-get install -y mongodb-org mongodb-org-server mongodb-org-shell mongodb-org-tools
+ apt:
+  sources:
+    - mongodb-upstart
+  packages:
+    - mongodb-org
+    - mongodb-org-server
+    - mongodb-org-shell
+    - mongodb-org-tools
 
 before_script:
   - "until nc -z localhost 27017; do echo Waiting for MongoDB; sleep 1; done"