fsouza/go-dockerclient — pull request #140 by kimh (2014-08-23 12:20:58+00:00)
Title: container: Add ContainerAlreadyRunning and ContainerNotRunning error

Docker returns http.StatusNotFound (304) when trying to (start|stop)
a container that is (already|not) started.

container should return proper error for the HTTP status code.