cmd/cli: skip deactivation check for old socket server

If the server is running old version of ctrld, the deactivation pin
check will return 404 not found, the client should consider this as no
error instead of returning invalid pin code.

This allows v1.3.5 binary `ctrld start` command while the ctrld server
is still running old version. I discover this while testing v1.3.5
binary on a router with old ctrld version running.

cmd/cli/cli.go

@@ -2194,6 +2194,8 @@ func checkDeactivationPin(s service.Service) error {
 			return errRequiredDeactivationPin // pin is required
 		case http.StatusOK:
 			return nil // valid pin
+		case http.StatusNotFound:
+			return nil // the server is running older version of ctrld
 		}
 	}
 	mainLog.Load().Error().Msg(errInvalidDeactivationPin.Error())