Fix docker::service: Pass the $docker::dns setting to the /etc/default/docker.erb template.
Fix docker::service: Fix the /etc/conf.d/docker.erb template to use the $dns setting.
Fix docker::service: Fix the /etc/sysconfig/docker.erb template to use the $dns setting.
Fix docker::service: Add unit tests for the $dns parameter.
Add a $dns_search parameter to docker::run.
Improve docker::service: Clean up the config templates.
Add a $dns_search parameter to the docker module.