Update Docker to 1.9.1
Update Docker to 1.9.1

ljharb/travis-cookbooks,travis-ci/travis-cookbooks,spurti-chopra/travis-cookbooks,travis-ci/travis-cookbooks,ljharb/travis-cookbooks,spurti-chopra/travis-cookbooks,travis-ci/travis-cookbooks,ljharb/travis-cookbooks,spurti-chopra/travis-cookbooks