run tests in ubuntu 1604

.travis.yml

@@ -1,6 +1,7 @@
 ---
 language: python
 python: "2.7"
+distro: ubuntu1604 # apt-key no longer works on 1404
 before_install:
  - sudo apt-get update -qq
  - sudo apt-get install -qq python-apt python-pycurl
@@ -13,7 +14,6 @@ install:
   # Install dependencies
   - ansible-galaxy install -r tests/requirements.yml
 script:
-  - which python ; which pip ; which ansible-playbook
   - echo localhost > inventory
 
   # Syntax check