docker/docker — pull request #9143 by coolljt0725 (2014-11-13 08:36:27+00:00)
Title: Cleanup:change latest to graph.DEFAULTTAG

Signed-off-by: Lei Jitang

I don't know if this is necessary or not,if not, feel free to close this.
But for a good coding style, it's better to use a global constant.
And some place also use `grath.DEFAULTTAG` instead of `latest`
https://github.com/docker/docker/blob/master/daemon/create.go#L43