docker/docker — pull request #7603 by kuon (2014-08-17 14:24:27+00:00)
Title: Added manual installation instruction for Centos7.

## Documentation
Added a note about firewalld.
Added manual installation instructions.

## Init service (systemd)
Ensure the docker daemon is started after firewalld.
Added "install" directive to docker service for systemd.

Signed-off-by: Nicolas Goy