deregister containers before removing driver and containerGraph references

This is required to address a race condition described in #5553,
where a container can be partially deleted -- for example, the
root filesystem but not the init filesystem -- which makes
it impossible to delete the container without re-adding the
missing filesystems manually.

This behavior has been witnessed when rebooting boxes that
are configured to remove containers on shutdown in parallel
with stopping the Docker daemon.

Docker-DCO-1.1-Signed-off-by: Gabriel Monroy <gabriel@opdemand.com> (github: gabrtv)

daemon/daemon.go

@@ -272,6 +272,10 @@ func (daemon *Daemon) Destroy(container *Container) error {
 		return err
 	}
 
+	// Deregister the container before removing its directory, to avoid race conditions
+	daemon.idIndex.Delete(container.ID)
+	daemon.containers.Remove(element)
+
 	if err := daemon.driver.Remove(container.ID); err != nil {
 		return fmt.Errorf("Driver %s failed to remove root filesystem %s: %s", daemon.driver, container.ID, err)
 	}
@@ -285,9 +289,6 @@ func (daemon *Daemon) Destroy(container *Container) error {
 		utils.Debugf("Unable to remove container from link graph: %s", err)
 	}
 
-	// Deregister the container before removing its directory, to avoid race conditions
-	daemon.idIndex.Delete(container.ID)
-	daemon.containers.Remove(element)
 	if err := os.RemoveAll(container.root); err != nil {
 		return fmt.Errorf("Unable to remove filesystem for %v: %v", container.ID, err)
 	}