removed docker

.travis.yml

@@ -2,12 +2,6 @@ language: bash
 dist: trusty
 sudo: required
 
-services:
-  - docker
-
-before_install:
-  - docker pull koalaman/shellcheck
-
 before_script:
     - curl -L "https://storage.googleapis.com/google-code-archive-downloads/v2/code.google.com/shunit2/shunit2-2.1.6.tgz" | tar zx