ctdb-config: Change example recovery lock setting to one that fails

ctdb-config: Change example recovery lock setting to one that fails

ctdbd will start without a recovery lock configured.  It will log a
message saying that this is not optimal.  However, a careless user may
overlook both this message and the importance of setting a recovery
lock.  If the existing example configuration is uncommented then the
directory containing it will be created (by 01.reclock.script) and the
failure (i.e. multiple nodes able to take the lock) will be confusing.

Instead, change the example setting to one that will result in banned
nodes, encouraging users to consciously configure (or deconfigure) the
recovery lock.  Tweak the corresponding comment.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=13790

Signed-off-by: Martin Schwenke <martin@meltin.net>
Reviewed-by: Amitay Isaacs <amitay@gmail.com>
(cherry picked from commit 82e7f38214896c2c200132bc6dde3348cfac16cc)