lxd-stophook-wrapper: Adds stop hook wrapper for the lxd command

This command is intended to replace the `lxd` command in the snap so that
existing running containers that are stopping will call this script as part of
their stop hooks.

This will then "route" the command to the `lxd-user` command that will be
statically compiled so that it can connect to the running LXD daemon via
the unix socket to indicate the container is stopping, even after refreshing
the LXD snap to a different core base snap.

Signed-off-by: Thomas Parrott <[email protected]>

lxd-stophook-wrapper/lxd

@@ -0,0 +1,8 @@
+#!/bin/sh
+# Use exec so that this script process is replaced.
+# This avoids polluting the process tree with this wrapper script.
+if [ "$1" = "callhook" ]; then
+    exec /snap/lxd/current/bin/lxd-user "$@"
+else
+    exec lxd "$@"
+fi