Fixes several issues with the pre/postremove scripts for both rpm and
deb packages. Specifically:
For postremove:
- the postremove script now functions correctly (i.e. restarts consul
after a package upgrade) on rpm-based systems (where $1 is numeric
rather than `purge` or `upgrade`)
- `systemctl daemon-reload` is called on package removal (rather than
only on upgrade)
- calls `systemctl try-restart` instead of `systemctl restart`, which
will only (re)start consul if it was already running when the upgrade
happened.
For preremove:
- if the package is being completely uninstalled (rather than upgraded),
stop consul before removing the package
