smbd: add option "smbd lease break:debug hung procs"

smbd: add option "smbd lease break:debug hung procs"

By enabling this a process sending a lease break message to another process
holding a lease will start watching that process and if that process didn't
process the lease break within 10 seconds (cf server_id_watch_waited()), we log
a kernel stack backtrace of that process.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=15624

Pair-Programmed-With: Stefan Metzmacher <metze@samba.org>

Signed-off-by: Ralph Boehme <slow@samba.org>
Signed-off-by: Stefan Metzmacher <metze@samba.org>
Reviewed-by: Guenther Deschner <gd@samba.org>