Migrate exec command to cobra

Signed-off-by: Akihiro Suda <suda.akihiro@lab.ntt.co.jp>
Upstream-commit: 9d9dff3d0d9e92adf7c2e59f94c63766659d1d47
Component: engine

components/engine/cli/cobraadaptor/adaptor.go

@@ -52,6 +52,7 @@ func NewCobraAdaptor(clientFlags *cliflags.ClientFlags) CobraAdaptor {
 		container.NewCopyCommand(dockerCli),
 		container.NewCreateCommand(dockerCli),
 		container.NewDiffCommand(dockerCli),
+		container.NewExecCommand(dockerCli),
 		container.NewExportCommand(dockerCli),
 		container.NewKillCommand(dockerCli),
 		container.NewLogsCommand(dockerCli),

components/engine/cli/usage.go

@@ -8,7 +8,6 @@ type Command struct {
 
 // DockerCommandUsage lists the top level docker commands and their short usage
 var DockerCommandUsage = []Command{
-	{"exec", "Run a command in a running container"},
 	{"inspect", "Return low-level information on a container, image or task"},
 }