If the target vsn is in `unpacked` state, but the release dir
`releases/<vsn>` is removed, then installing the target vsn
again will fail with error `{error,enoent}`.
In this case we should extract the tar ball again and then continue
to install the release.
for remsh prefixed nodes, ekka pick a random port to listen on
instead of following the conventional port mapping rule:
ekka listens on 4370 for emqx or emqx0 and 4371 for
emqx1 and so on
Zaiming (Stone) Shi