doc/mgr/dashboard: Fix HAProxy TLS example

With `ssl` set on the `server` option, HAProxy strips the TLS protocol
for all clients. You would need to connect to it with `http://<ip>:443`.

To have an active health check, which uses SSL, but does not strip it
for clients, you'd need to add:

- `check` to enable active health checks.
- `check-ssl` to instruct the health check to use TLS
- `verify none` to skip verification on the health check requests from
  HAProxy
- _REMOVE_ `ssl` to stop stripping TLS

The active health checks are required to not route any requests to the
inactive managers. These would redirect to any unusable IP from the
active mgr.

---

Alternatively you could add another certificate in the frontend and then
re-encrypt the traffic. But this would require tracking the certs also
in HAProxy.

Signed-off-by: Benedikt Heine <[email protected]>

doc/mgr/dashboard.rst

@@ -1296,9 +1296,9 @@ redirection on standby nodes.
     mode tcp
     option httpchk GET /
     http-check expect status 200
-    server x <HOST>:<PORT> ssl check verify none
-    server y <HOST>:<PORT> ssl check verify none
-    server z <HOST>:<PORT> ssl check verify none
+    server x <HOST>:<PORT> check check-ssl verify none
+    server y <HOST>:<PORT> check check-ssl verify none
+    server z <HOST>:<PORT> check check-ssl verify none
 
 .. _dashboard-auditing: