new "image" mount type

Add a new "image" mount type to `--mount`.  The source of the mount is
the name or ID of an image.  The destination is the path inside the
container.  Image mounts further support an optional `rw,readwrite`
parameter which if set to "true" will yield the mount writable inside
the container.  Note that no changes are propagated to the image mount
on the host (which in any case is read only).

Mounts are overlay mounts.  To support read-only overlay mounts, vendor
a non-release version of Buildah.

Signed-off-by: Valentin Rothberg <rothberg@redhat.com>

vendor/github.com/fsouza/go-dockerclient/container_start.go

@@ -0,0 +1,56 @@
+package docker
+
+import (
+	"context"
+	"net/http"
+)
+
+// StartContainer starts a container, returning an error in case of failure.
+//
+// Passing the HostConfig to this method has been deprecated in Docker API 1.22
+// (Docker Engine 1.10.x) and totally removed in Docker API 1.24 (Docker Engine
+// 1.12.x). The client will ignore the parameter when communicating with Docker
+// API 1.24 or greater.
+//
+// See https://goo.gl/fbOSZy for more details.
+func (c *Client) StartContainer(id string, hostConfig *HostConfig) error {
+	return c.startContainer(id, hostConfig, doOptions{})
+}
+
+// StartContainerWithContext starts a container, returning an error in case of
+// failure. The context can be used to cancel the outstanding start container
+// request.
+//
+// Passing the HostConfig to this method has been deprecated in Docker API 1.22
+// (Docker Engine 1.10.x) and totally removed in Docker API 1.24 (Docker Engine
+// 1.12.x). The client will ignore the parameter when communicating with Docker
+// API 1.24 or greater.
+//
+// See https://goo.gl/fbOSZy for more details.
+//nolint:golint
+func (c *Client) StartContainerWithContext(id string, hostConfig *HostConfig, ctx context.Context) error {
+	return c.startContainer(id, hostConfig, doOptions{context: ctx})
+}
+
+func (c *Client) startContainer(id string, hostConfig *HostConfig, opts doOptions) error {
+	path := "/containers/" + id + "/start"
+	if c.serverAPIVersion == nil {
+		c.checkAPIVersion()
+	}
+	if c.serverAPIVersion != nil && c.serverAPIVersion.LessThan(apiVersion124) {
+		opts.data = hostConfig
+		opts.forceJSON = true
+	}
+	resp, err := c.do(http.MethodPost, path, opts)
+	if err != nil {
+		if e, ok := err.(*Error); ok && e.Status == http.StatusNotFound {
+			return &NoSuchContainer{ID: id, Err: err}
+		}
+		return err
+	}
+	defer resp.Body.Close()
+	if resp.StatusCode == http.StatusNotModified {
+		return &ContainerAlreadyRunning{ID: id}
+	}
+	return nil
+}