packaging: fix issues in pre/postremove scripts (#12147)

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

.github/workflows/build.yml

@@ -3,7 +3,7 @@ name: build
 on:
   push:
     # Sequence of patterns matched against refs/heads
-    branches: [ 
+    branches: [
       "main"
     ]
 
@@ -145,6 +145,7 @@ jobs:
           config_dir: ".release/linux/package"
           preinstall: ".release/linux/preinstall"
           postinstall: ".release/linux/postinstall"
+          preremove: ".release/linux/preremove"
           postremove: ".release/linux/postremove"
 
       - name: Set Package Names

.release/linux/postremove

@@ -1,14 +1,19 @@
 #!/bin/bash
 
-if [ "$1" = "purge" ]
-then
-  userdel consul
+if [ -d "/run/systemd/system" ]; then
+    systemctl --system daemon-reload >/dev/null || :
 fi
 
-if [ "$1" == "upgrade" ] && [ -d /run/systemd/system ]; then
-  systemctl --system daemon-reload >/dev/null || true
-  systemctl restart consul >/dev/null || true
-fi
+case "$1" in
+    purge | 0)
+        userdel consul
+        ;;
 
-exit 0
+    upgrade | [1-9]*)
+        if [ -d "/run/systemd/system" ]; then
+            systemctl try-restart consul.service >/dev/null || :
+        fi
+        ;;
+esac
 
+exit 0

.release/linux/preremove

@@ -0,0 +1,11 @@
+#!/bin/bash
+case "$1" in
+    remove | 0)
+        if [ -d "/run/systemd/system" ]; then
+            systemctl --no-reload disable consul.service > /dev/null || :
+            systemctl stop consul.service > /dev/null || :
+        fi
+        ;;
+esac
+
+exit 0