snap: Fix static dir on upgrades
snap: Fix static dir on upgrades

Signed-off-by: Stéphane Graber <089afc6d81f66f1168a9849e15660feae286e024@ubuntu.com>

lxc/lxd-demo-server,lxc/lxd-demo-server,lxc/lxd-demo-server,lxc/lxd-demo-server