Auto-enable early release for offline old nodes

In case the old node is offline, we won't be able to talk to it to
remove the storage, and in most cases the node is powered
off/unreachable.

In this case, it makes no sense to delay the storage release, so we
enable automatically early_release mode, gaining parallelism during node
evacuation.

Signed-off-by: Iustin Pop <iustin@google.com>
Reviewed-by: Michael Hanselmann <hansmi@google.com>