docker/docker — pull request #8818 by coolljt0725 (2014-10-28 12:45:14+00:00)
Title: Fix docker exec help messages.

Signed-off-by: Lei Jitang

The docker exec command help messages "Run a command in an existing container"
should be "Run a command in an running container".
"an existing container" would confuse the users since docker exec exactly run a command
in a running container.
docker-exec.1.md also description the docker exec command as
"Run a process in a running container."