Start docker service after installation

[mvandeberg]

Brief description

Starts the Docker service after installation

Checklist

• [ ] I have built this pull request locally
• [ ] I have ran the unit tests locally
• [ ] I have manually tested this pull request
• [X] I have reviewed my pull request
• [ ] I have added any relevant tests

Demonstration

[sgerbino]

I re-ran master and CI passed, is this necessary? Or did just get lucky on which Travis CI image decide to run?