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
OTP release handler only works with .tar.gz
as a result, we had to unpack .zip and re-pack .tar.gz
just to make OTP happy.
Now since we will be building .tar.gz packages
there is no need for this re-pack step anymore
The `install_upgrade.escript` depended on being able to retrieve the
`vm_args` argument from `init`, but that options has been removed
recently. Since this backup was unused, we also remove it here.
Zaiming (Stone) Shi