Enable inspect exec if container is pause/restarting/non-running

[coolljt0725]

if docker exec exit and at the same the the container is pause,
there could be a chance the docker exec exit will fail

$ docker exec -ti 388c7f47a06c sh
/ # exit
Error response from daemon: Container 388c7f47a06cce0856266ffd56a2ce2901689ca7a6b9cd741b37652418448f2b is paused, unpause the container before exec

To reproduce this error easilly, we can add a sleep in containerPause

--- a/daemon/pause.go
+++ b/daemon/pause.go
@@ -2,6 +2,7 @@ package daemon

 import (
        "fmt"
+       "time"

        "github.com/docker/docker/container"
 )
@@ -25,7 +26,7 @@ func (daemon *Daemon) ContainerPause(name string) error {
 func (daemon *Daemon) containerPause(container *container.Container) error {
        container.Lock()
        defer container.Unlock()
-
+       time.Sleep(time.Second * 5)
        // We cannot Pause the container which is not running
        if !container.Running {
                return errNotRunning{container.ID}

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[allencloud]

I am not sure that the design is ok. While I think here we can simplify the code like format:

e := daemon.execCommands.Get(id)
if e == nil {
        return nil, errExecNotFound(id)
}

if container := daemon.containers.Get(e.ContainerID); container == nil {
        return nil, errExecNotFound(id)
}

[coolljt0725]

That's better, done

[boaz0]

LGTM.
Another way I could think of is to handle the error coming from getExecConfig but that's much cleaner!

[cpuguy83]

LGTM

[thaJeztah]

LGTM