Fixed bad handling of "container not found" error

Create container job could fail because a container specified with
`--volumes-from` does not exist. This error is not propagated to client
though. Instead it's recognized by higher levels as "image not found".
Client then tries to pull the image and launch the container again.

This patch changes the lower level error message so that it's not
recognized as "image not found" and thus it's propagated to client.

Signed-off-by: Michal Minar <miminar@redhat.com>

daemon/volumes.go

@@ -279,7 +279,7 @@ func (container *Container) applyVolumesFrom() error {
 
 		c, err := container.daemon.Get(id)
 		if err != nil {
-			return err
+			return fmt.Errorf("Could not apply volumes of non-existent container %q.", id)
 		}
 
 		var (