ensure-container-stopped.sh: don't fail on launchctl errors (#1461)

- Fixes #1281. Supersedes #1306.
- When `-a` runs as a regular user (such as via
  `brew install container`), two launchctl failures
  bubble up as a non-zero exit and break Homebrew's
  post-install:
  - `bootout` against `system` requires root.
  - `launchctl print` lists Mach endpoint names that
    aren't loaded jobs, so `bootout` returns
    `No such process` on them.
- Skip `system` when not root, and treat individual
  `bootout` failures as non-fatal. Same fix applied to
  the non-`-a` `xargs` pipeline.

Signed-off-by: Patrick Linnane <patrick@linnane.io>

scripts/ensure-container-stopped.sh

@@ -44,11 +44,14 @@ done
 if $ALL_DOMAINS; then
     uid=$(id -u)
     for domain in "gui/$uid" "user/$uid" "system"; do
+        if [ "$domain" = "system" ] && [ "$uid" -ne 0 ]; then
+            continue
+        fi
         launchctl print "$domain" 2>/dev/null \
             | grep -oE 'com\.apple\.container\.[^ ]+' \
             | sort -u \
             | while read -r service; do
-                launchctl bootout "$domain/$service"
+                launchctl bootout "$domain/$service" 2>/dev/null || true
             done
     done
 else
@@ -67,5 +70,6 @@ else
         exit 1
     fi
 
-    launchctl list | grep -e 'com\.apple\.container\W' | awk '{print $3}' | xargs -I % launchctl bootout $domain_string/%
+    launchctl list | grep -e 'com\.apple\.container\W' | awk '{print $3}' \
+        | xargs -I % sh -c 'launchctl bootout '"$domain_string"'/% 2>/dev/null || true'
 fi