api: remove POST /containers/{id}/copy endpoint (api < v1.23)

This endpoint was deprecated in API v1.20 (Docker Engine v1.8.0) in
commit db9cc91a9e, in favor of the
`PUT /containers/{id}/archive` and `HEAD /containers/{id}/archive`
endpoints, and disabled in API v1.24 (Docker Engine v1.12.0) through
commit 428328908d.

This patch removes the endpoint, and the associated `daemon.ContainerCopy`
method in the backend.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

daemon/archive_unix.go

@@ -161,55 +161,6 @@ func (daemon *Daemon) containerExtractToDir(container *container.Container, path
 	return nil
 }
 
-func (daemon *Daemon) containerCopy(container *container.Container, resource string) (rc io.ReadCloser, err error) {
-	container.Lock()
-
-	defer func() {
-		if err != nil {
-			// Wait to unlock the container until the archive is fully read
-			// (see the ReadCloseWrapper func below) or if there is an error
-			// before that occurs.
-			container.Unlock()
-		}
-	}()
-
-	cfs, err := daemon.openContainerFS(container)
-	if err != nil {
-		return nil, err
-	}
-	defer func() {
-		if err != nil {
-			cfs.Close()
-		}
-	}()
-
-	err = cfs.RunInFS(context.TODO(), func() error {
-		_, err := os.Stat(resource)
-		return err
-	})
-	if err != nil {
-		return nil, err
-	}
-
-	tb, err := archive.NewTarballer(resource, &archive.TarOptions{
-		Compression: archive.Uncompressed,
-	})
-	if err != nil {
-		return nil, err
-	}
-
-	cfs.GoInFS(context.TODO(), tb.Do)
-	archv := tb.Reader()
-	reader := ioutils.NewReadCloserWrapper(archv, func() error {
-		err := archv.Close()
-		_ = cfs.Close()
-		container.Unlock()
-		return err
-	})
-	daemon.LogContainerEvent(container, events.ActionCopy)
-	return reader, nil
-}
-
 // checkIfPathIsInAVolume checks if the path is in a volume. If it is, it
 // cannot be in a read-only volume. If it  is not in a volume, the container
 // cannot be configured with a read-only rootfs.